Sheet metal connecting screw

Abstract

The utility model discloses a metal plate connecting screw which comprises a nut and a screw rod which are connected with each other, and is characterized in that the screw rod comprises a thread locking section and a thread self-tapping section, the thread locking section is connected with the nut, one end of the thread self-tapping section is connected with a bottom hole forming section used for correcting a bottom hole, and the other end of the thread self-tapping section is connected with a screw rod. One end of the bottom hole forming section is connected with a bottom hole punching section used for forming a rough bottom hole in the metal plate through impact. The connecting structure has the advantages of being capable of achieving efficient and reliable connection, simplifying manufacturing procedures and reducing weight and cost.

Description

Technical Field

[0001] The utility model relates to a screw, in particular to a sheet metal connecting screw. Background Art

[0002] In the modern automobile manufacturing industry, efficient and reliable connection of sheet metal parts is a key link to ensure the stability and safety of the body structure. Although traditional sheet metal connection methods, such as bolt and nut connection, spot welding connection and glue bonding, perform well in terms of strength and reliability, their application has significant limitations.

[0003] First, bolted connections require pre-drilling of sheet metal, which increases the complexity and cost of the manufacturing process. Drilling is not only time-consuming and labor-intensive, but can also lead to stress concentration in metal materials, thus affecting the overall stability of the structure. In addition, the use of bolts and nuts increases the total weight of the vehicle, which runs counter to the current trend of the automotive industry in pursuit of lightweighting, which can not only improve fuel efficiency, but also extend the range of electric vehicles. Therefore, traditional bolted connection methods are difficult to meet the needs of modern automobile manufacturing for lightweight and efficient production.

[0004] Although spot welding connection technology can achieve quick connection without the need for additional parts, its investment cost for equipment is extremely high, which limits its widespread application. More importantly, when faced with sheet metal connections of different materials (such as mixed connections of aluminum alloys and steel), spot welding technology often seems to be unable to cope with it. During the welding process, due to the different thermal expansion coefficients and melting points of different materials, the welding quality is difficult to guarantee, which may lead to insufficient strength of the connection parts or cracks, thereby affecting the overall reliability of the body structure.

[0005] In addition, as an emerging technology, solid glue bonding simplifies the connection process and reduces the weight of the vehicle, but its bonding strength is relatively low. Solid glue has poor durability and resistance to environmental factors under high load or extreme working conditions (such as environments with drastic changes in temperature and humidity), which significantly limits its application in the automotive manufacturing field. The bonding parts may experience aging, degumming and other problems during long-term use, posing potential safety hazards.

[0006] In summary, the existing sheet metal connection methods have their own shortcomings in automobile manufacturing and cannot fully meet the requirements of modern automobiles for high efficiency, reliability, lightweight and adaptability to complex working conditions. Therefore, a new sheet metal connection method is urgently needed to solve the above problems, ensure the stability and safety of the body structure, simplify the manufacturing process, reduce production costs, and adapt to the lightweight trend of the automotive industry. Utility Model Content

[0007] The purpose of the utility model is to solve the above-mentioned problems and provide a sheet metal connecting screw, which can achieve efficient and reliable connection, simplify the manufacturing process, and reduce weight and cost.

[0008] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions: a sheet metal connecting screw, comprising a nut and a screw rod connected to each other, the screw rod comprising a thread locking section and a thread self-tapping section, the thread locking section is connected to the nut, one end of the thread self-tapping section is connected to a bottom hole forming section for correcting the bottom hole, and one end of the bottom hole forming section is connected to a bottom hole punching section for forming a rough bottom hole in the sheet metal through impact.

[0009] Preferably, the end of the bottom hole punching section has a pointed portion, the surface of the pointed portion is carburized, the core hardness is 320-400 HV, the surface hardness is 450-520 HV, and the carburizing depth is 0.1-0.25 mm.

[0010] Preferably, the bottom hole punching section is a rod body with an axial gradient, and the diameter of the bottom hole punching section gradually increases from the pointed portion to the bottom hole forming section.

[0011] Preferably, the bottom hole forming section is reamed in the shape of a Reuleaux triangle, and a plurality of triangular edges are arranged in the circumference thereof.

[0012] Preferably, the thread of the self-tapping thread section is a self-tapping triangular thread, the thread depth of the self-tapping thread section is 0.3-0.7 mm, the thread pitch is 0.6-1.2 mm, and the thread angle is 45-75 degrees.

[0013] Preferably, the thread locking section has a thread depth of 0.5-1.5 mm, a thread pitch of 0.8-1.5 mm, and a thread angle of 50-60 degrees.

[0014] Preferably, the nut is made of carbon steel or stainless steel, and the end of the nut is provided with a hexagonal or plum blossom-shaped head for twisting.

[0015] Preferably, the screw is made of carbon steel or stainless steel, the material strength of which is not less than 350 MPa, and the surface of the screw is sprayed, galvanized or phosphating treated.

[0016] Preferably, the bottom hole forming section is shorter than the thread self-tapping section, the thread self-tapping section is shorter than the bottom hole punching section, and the bottom hole punching section is shorter than the thread locking section.

[0017] Compared with the prior art, the advantages of the utility model are that the sheet metal connecting screw comprises a thread locking section, a thread self-tapping section, a bottom hole forming section and a bottom hole punching section. This segmented design effectively decomposes the connection process into multiple steps, corresponding to functions such as punching, reaming, self-tapping threading and locking. First, the sharp head of the bottom hole punching section forms a rough bottom hole on the sheet metal through impact force, laying the foundation for subsequent reaming and thread forming. Then, the bottom hole forming section accurately corrects the rough bottom hole by rotating with the help of its Leroy triangle-shaped reaming structure to form a smooth and high-quality bottom hole. The excess material generated at this stage is squeezed to flow to the lower plate, providing sufficient locking space for the subsequent self-tapping thread. Next, the self-tapping thread section forms a thread in the bottom hole by extrusion, thereby firmly connecting with the sheet metal. Finally, the thread locking section is tightened into the formed thread to complete the entire connection process.

[0018] This design not only simplifies the operation steps, without the need for additional tools or pre-drilling, but also optimizes the connection strength and material utilization. At the same time, thanks to its lightweight design, the screw significantly reduces the weight of the vehicle body, which is in line with the development trend of lightweight modern automobiles. In addition, the design is easy to produce and maintain, reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. It is obvious that the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0021] Figure 2 It is the front view of the utility model;

[0022] Figure 3 It is a side view of the utility model;

[0023] In the figure, 1, nut; 2, screw; 3, thread locking section; 4, thread self-tapping section; 5, bottom hole forming section; 6, bottom hole punching section; 7, pointed section; 8, head. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] Embodiment 1: As shown in the figure, a sheet metal connecting screw comprises a nut 1 and a screw rod 2 which are connected to each other, the screw rod 2 comprises a thread locking section 3 and a thread self-tapping section 4, the thread locking section 3 is connected to the nut 1, one end of the thread self-tapping section 4 is connected to a bottom hole forming section 5 for correcting the bottom hole, and one end of the bottom hole forming section 5 is connected to a bottom hole punching section 6 for forming a rough bottom hole in the sheet metal through impact.

[0026] The screw includes the following steps when working:

[0027] a) using the bottom hole punching section 6 to impact the sheet metal to form a rough bottom hole;

[0028] b) using the bottom hole forming section 5 to correct the bottom hole to form a smooth and qualified bottom hole;

[0029] c) forming threads in the bottom hole using a self-tapping thread section;

[0030] d) Using the thread locking section 3, screw the screw into the thread to complete the connection.

[0031] Embodiment 2: As shown in the figure, the difference from Embodiment 1 is that the end of the bottom hole punching section 6 has a pointed portion 7, the surface of the pointed portion 7 is carburized, the core hardness is 320-400HV, the surface hardness is 450-520HV, and the carburizing depth is 0.1-0.25mm.

[0032] The design of the sheet metal connecting screw adopts a pointed head 7 at the end of the bottom hole punching section 6 and performs a carburizing treatment. This design enhances the punching efficiency and the durability of the screw, and improves the stability of the connection. The pointed head 7 can penetrate the sheet metal more effectively, and the carburizing treatment gives the pointed head 7 higher hardness and wear resistance, so that it can remain sharp during multiple uses and avoid excessive wear or breakage.

[0033] Specifically, the carburizing treatment forms a carburized layer with high hardness and high wear resistance on the surface of the pointed part 7 by infiltrating carbon elements into the surface, while the core still maintains a certain toughness. This hardness gradient structure ensures that the pointed part 7 can easily penetrate the sheet metal and avoids excessive embrittlement and fracture; the core hardness range is 320-400HV, which ensures that the bottom hole punching section 6 can withstand a certain deformation when subjected to impact force, and the surface hardness range is 450-520HV, which ensures that it can remain sharp during continuous friction with the sheet metal, thereby improving punching efficiency and service life; the depth of the carburized layer is limited to 0.1-0.25mm, which can effectively improve the surface hardness and avoid material embrittlement caused by excessive carburizing.

[0034] In this embodiment, the bottom hole punching section 6 is a rod body with an axial gradient, and the diameter of the bottom hole punching section 6 gradually increases from the pointed portion 7 to the bottom hole forming section 5 .

[0035] The bottom hole punching section 6 of the sheet metal connecting screw adopts an axially gradual rod structure, and its diameter gradually increases from the pointed head 7 to the bottom hole forming section 5. This design cleverly balances the punching efficiency and stability. First, the smaller diameter of the pointed head 7 is conducive to improving the punching efficiency. When the screw is subjected to impact force, the pointed head 7 can quickly penetrate the sheet metal to form a rough bottom hole, and the gradually increasing rod body diameter provides a stronger supporting force in the subsequent punching process, avoiding the bending or breaking of the punching section during the impact process, and ensuring the stability and accuracy of the punching; secondly, the gradual rod body design can effectively control the impact force during the punching process to avoid excessive impact on the sheet metal. After the pointed head 7 penetrates the sheet metal, the gradually increasing rod body diameter can gradually disperse the impact force to a larger area, thereby reducing the impact intensity on the sheet metal, reducing vibration and noise, and reducing the risk of deformation and breakage of the sheet metal; in addition, this design is also conducive to improving the stability and service life of the punching section. The gradually increasing rod body diameter enhances the bending resistance of the punching section, making it less likely to deform or break when subjected to a large impact force, thereby extending the service life of the screw.

[0036] Embodiment 3: As shown in the figure, different from Embodiment 2, the bottom hole forming section 5 is reamed in the shape of a Reuleaux triangle, and a plurality of triangular edges are arranged in the circumferential direction.

[0037] The above design effectively improves the efficiency and quality of reaming and creates more ideal conditions for subsequent thread processing. The Releaux triangle, also known as the Releaux triangle, is a curve shape with special geometric properties. Since its curvature is continuous and always positive, it can ensure the formation of a smooth and uniform hole wall during reaming during the rotation process, effectively reducing burrs and burrs, and improving the accuracy and quality of the bottom hole. At the same time, the shape of the Releaux triangle also makes the reaming process smoother, reduces friction and resistance during the processing process, and reduces energy loss and noise.

[0038] The circumferentially arranged triangular edges further enhance the reaming effect. These edges can effectively control the flow direction of the metal material during rotation, squeezing the excess material to flow toward the lower plate, providing more space for subsequent thread processing. At the same time, the edges also help to improve the efficiency and stability of reaming, avoiding excessive deformation or breakage during the reaming process.

[0039] In this embodiment, the thread of the thread self-tapping section 4 is a self-tapping triangular thread, the thread depth of the thread self-tapping section 4 is 0.3-0.7 mm, the thread pitch is 0.6-1.2 mm, and the thread angle is 45-75 degrees.

[0040] In the above structure, the special shape of the triangular thread and the cooperation between the thread self-tapping section 4 and the bottom hole forming section 5 enable the screw to extrude the metal material during rotation to form a thread that is tightly combined with the sheet metal. This method does not require pre-tapping, simplifies the connection process, and improves production efficiency; the thread self-tapping section 4 is designed with a thread depth of 0.3-0.7mm, which not only ensures sufficient thread depth to be tightly combined with the sheet metal, but also avoids excessive pressure on the sheet metal caused by excessively deep threads, thereby ensuring the firmness and safety of the connection; the thread pitch of 0.6-1.2mm is adapted to the material and thickness of the sheet metal, and can improve the bite force of the thread while ensuring the strength of the thread, thereby preventing the thread from easily slipping off or breaking; the thread angle of 45-75 degrees ensures the strength of the thread, while ensuring that the thread can smoothly enter the bottom hole during the tightening process, thereby avoiding jamming or excessive friction, thereby improving operational efficiency and stability.

[0041] In this embodiment, the thread depth of the thread locking section 3 is 0.5-1.5 mm, the thread pitch is 0.8-1.5 mm, and the thread angle is 50-60 degrees.

[0042] In the above structure, the thread locking section 3 adopts special design parameters, the thread depth is 0.5-1.5mm, the thread pitch is 0.8-1.5mm, and the thread angle is 50-60 degrees. This design cooperates with the thread self-tapping section 4 to ensure that the screw can be firmly locked in the formed thread and provide sufficient connection strength to resist various external forces; the thread depth range is 0.5-1.5mm, which ensures that the thread can form sufficient bite with the self-tapping thread section, which not only improves the connection strength, but also can effectively prevent the screw from loosening or falling off during use; the thread pitch range is The pitch is 0.8-1.5mm. The larger pitch increases the grip of the thread, improves the friction between the thread and the sheet metal, and reduces the risk of loosening. At the same time, the larger pitch also helps to distribute the pressure more evenly, reduce the local stress concentration of the thread on the sheet metal, and thus improve the overall stability of the connection. The thread angle of 50-60 degrees is also an important parameter. A reasonable angle can ensure that the thread can be smoothly screwed into the formed thread, and at the same time provide sufficient strength to resist the effects of tension and torsional forces. Too small an angle will reduce the strength of the thread, while too large an angle will make the tightening process difficult.

[0043] Embodiment 4: As shown in the figure, different from Embodiment 3, the nut 1 is made of carbon steel or stainless steel, and the end of the nut 1 is provided with a hexagonal or plum blossom-shaped head 8 for twisting.

[0044] In the above structure, the nut 1 made of carbon steel or stainless steel ensures the strength and corrosion resistance of the nut 1. Carbon steel has high strength and toughness and can withstand high-load connections, while stainless steel has good corrosion resistance and can resist corrosion in harsh environments, thereby extending the service life of the screw. The hexagonal or plum blossom-shaped head arranged at the end of the nut 1 facilitates installation and disassembly operations, and the nut 1 can be easily tightened or loosened using a wrench or socket wrench, thereby simplifying the operation process and improving installation efficiency.

[0045] In this embodiment, the screw rod 2 is made of carbon steel or stainless steel, the material strength of which is not less than 350 MPa, and the surface of the screw rod 2 is spray-coated, galvanized or phosphating treated.

[0046] The selection of carbon steel and stainless steel meets the requirements of different strength and corrosion resistance respectively. Carbon steel has high strength and toughness, can withstand large loads and impacts, and is suitable for high-strength connection occasions. Stainless steel has good corrosion resistance and can resist erosion in various harsh environments. It is suitable for occasions that are greatly affected by moisture, acid and alkali environments. The setting of material strength of not less than 350Mpa ensures that the screw 2 can withstand large tensile and torsional forces during the connection process, and can also prevent the screw 2 from bending or breaking when impacted, ensuring the stability and safety of the connection. Spraying, galvanizing or phosphating treatment on the surface of the screw 2 further enhances the corrosion resistance and service life of the screw 2. Spraying can form a dense protective layer to prevent the screw 2 from contacting the external environment and extend its service life. Galvanizing enhances its corrosion resistance by forming a zinc layer on the surface of the screw 2, which is particularly suitable for use in humid or acidic environments. Phosphating prevents corrosion by forming a phosphate protective layer, and can also improve the wear resistance of the screw, making it more durable in application. When using, select the corresponding surface treatment technology according to the corresponding application scenario.

[0047] In this embodiment, the bottom hole forming section 5 is shorter than the thread self-tapping section 4 , the thread self-tapping section 4 is shorter than the bottom hole punching section 6 , and the bottom hole punching section 6 is shorter than the thread locking section 3 .

[0048] The design of the sheet metal connecting screw adopts a specific proportional relationship in the length of each part. The bottom hole forming section 5 is shorter than the thread self-tapping section 4, the thread self-tapping section 4 is shorter than the bottom hole punching section 6, and the bottom hole punching section 6 is shorter than the thread locking section 3. This design cleverly balances the functional requirements of each part, ensures the smooth completion of the connection process, and improves the reliability of the connection.

[0049] The shorter design of the bottom hole forming section 5 ensures the efficiency and accuracy of the reaming process. The short length enables the bottom hole forming section 5 to be more accurately positioned in the rough hole after punching, and the hole wall can be quickly corrected into a smooth and uniform shape by rotation, avoiding excessive friction or deformation caused by excessive contact.

[0050] The threaded self-tapping section 4 is slightly longer than the bottom hole forming section 5. This is to ensure that the self-tapping thread can completely enter the bottom hole, forming a sufficiently deep thread depth to ensure a firm connection with the sheet metal. If the threaded self-tapping section 4 is too short, it may result in insufficient threads and affect the connection strength; if it is too long, it may affect the installation operation and even cause excessive tightening to cause deformation of the sheet metal.

[0051] The length of the bottom hole punching section 6 is relatively longer, which is to ensure sufficient impact force and stability during the punching process. The longer punching section can withstand greater impact force to avoid bending or breaking during the punching process. At the same time, it can also more effectively transfer the impact force to the sheet metal to ensure the smooth completion of the punching process.

[0052] The thread locking section 3 is the longest, not only to ensure sufficient locking length, but more importantly, it can effectively prevent the screw from loosening or falling off during use. The longer thread locking section 3 can better contact and bite the formed thread, thereby improving the stability and reliability of the connection.

[0053] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A sheet metal connection screw, comprising a nut and a screw connected to each other, characterized in that: The screw rod includes a thread locking section and a thread self-tapping section, the thread locking section is connected to the nut, one end of the thread self-tapping section is connected to a bottom hole forming section for correcting the bottom hole, and one end of the bottom hole forming section is connected to a bottom hole punching section for forming a rough bottom hole on the sheet metal through impact.

2. A sheet metal connecting screw according to claim 1, characterized in that: The end of the bottom hole punching section has a pointed portion, the surface of the pointed portion is carburized, the core hardness is 320-400 HV, the surface hardness is 450-520 HV, and the carburization depth is 0.1-0.25 mm.

3. The sheet metal connecting screw according to claim 2, characterized in that: The bottom hole punching section is a rod body with an axial gradient, and the diameter of the bottom hole punching section gradually increases from the pointed portion to the bottom hole forming section.

4. The sheet metal connecting screw according to claim 1, characterized in that: The bottom hole forming section is reamed in the shape of a Reuleaux triangle, and a plurality of triangular edges are arranged in the circumference thereof.

5. The sheet metal connecting screw according to claim 1, characterized in that: The thread of the thread self-tapping section is a self-tapping triangular thread, the thread depth of the thread self-tapping section is 0.3-0.7 mm, the thread pitch is 0.6-1.2 mm, and the thread angle is 45-75 degrees.

6. The sheet metal connecting screw according to claim 1, characterized in that: The thread locking section has a thread depth of 0.5-1.5 mm, a thread pitch of 0.8-1.5 mm, and a thread angle of 50-60 degrees.

7. The sheet metal connecting screw according to claim 1, characterized in that: The material of the nut is carbon steel or stainless steel, and the end of the nut is provided with a hexagonal or plum blossom-shaped head for twisting.

8. The sheet metal connecting screw according to claim 1, characterized in that: The screw is made of carbon steel or stainless steel, the material strength of which is not less than 350 MPa, and the surface of the screw is sprayed, galvanized or phosphated.

9. The sheet metal connecting screw according to claim 1, characterized in that: The bottom hole forming section is shorter than the thread self-tapping section, the thread self-tapping section is shorter than the bottom hole punching section, and the bottom hole punching section is shorter than the thread locking section.

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