Self-extruding bolts with self-lubricating function
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI KUYAO NEW MATERIAL CO LTD
- Filing Date
- 2025-07-24
- Publication Date
- 2026-06-30
AI Technical Summary
The application of lubricant during the assembly of self-extruding bolts affects the assembly rhythm. The type and amount of lubricant are difficult to control, resulting in an unstable coefficient of friction, which affects the assembly torque and anti-loosening performance.
An electroplated layer is applied to the thread structure of the bolt, and a lubricating layer is then applied over it. The thread structure is a circular arc triangle, and the lubricating layer covers a length of 30% or more. Combined with the anti-loosening teeth at the bolt head, a self-lubricating effect is achieved.
No pre-applied lubricant is required; the lubricating layer is evenly applied during bolt assembly, reducing the tapping torque, improving anti-loosening performance, increasing thread strength, preventing rotation, and enhancing assembly stability.
Smart Images
Figure CN224433066U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of bolt technology, specifically to a self-extruding bolt with self-lubricating function. Background Technology
[0002] Self-extruding bolts offer unique advantages in various scenarios: they can be installed simply by drilling, eliminating the need for tapping, preserving the strength of the base metal, and reducing metal debris. The thread cross-section of a self-extruding bolt is triangular, making it difficult to rotate after assembly due to the plastic deformation of the base metal, thus providing excellent anti-loosening performance. However, the application of self-extruding bolts is somewhat limited by the following factors: 1) assembly requires the application of lubricant, affecting the assembly rhythm; 2) the type and amount of lubricant applied can affect the coefficient of friction, making it difficult to establish a consistent standard for assembly torque. Utility Model Content
[0003] In view of the deficiencies in the prior art, the purpose of this utility model is to provide a self-extruding bolt with self-lubricating function.
[0004] A self-extruding bolt with self-lubricating function according to this utility model includes:
[0005] The bolt body includes a screw head and a screw rod, wherein the screw head is connected to one end of the screw rod, and the screw rod is provided with a threaded structure;
[0006] An electroplated layer covers the surface of the threaded structure;
[0007] A lubricating layer covers the electroplated layer and extends from the other end of the screw toward the screw head;
[0008] The cross-sectional shape of the threaded structure is a circular arc triangle, and the coverage length of the lubricating layer is greater than or equal to 30% of the total length of the threaded structure.
[0009] Preferably, the electroplated layer is a zinc layer or a zinc-nickel alloy layer.
[0010] Preferably, the thickness of the lubricating layer is 0.5 mm to 1 mm.
[0011] Preferably, the lubricating layer is a cured lubricant structure.
[0012] Preferably, the friction coefficient of the lubricating layer is μ, where μ ≤ 0.07.
[0013] Preferably, the tapping torque of the thread structure is M Nm, the nominal diameter of the thread structure is N mm, and M≤4N.
[0014] Preferably, the connection point between the screw head and the screw rod is provided with anti-loosening teeth.
[0015] Preferably, the coverage length of the lubricating layer is less than or equal to 70% of the total length of the thread structure.
[0016] Preferably, the screw head is a hexagonal head.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] 1. This utility model provides a lubricating layer at the head of the screw. During bolt assembly, the lubricating layer covers the entire thread structure under the action of compression, achieving overall lubrication of the thread. This eliminates the need to apply lubricant before assembly and does not affect the assembly rhythm.
[0019] 2. This utility model adopts a threaded structure with a circular arc triangular cross section. The threaded structure is driven into the pre-drilled hole in the substrate and the thread is generated by extrusion. This preserves the internal texture of the substrate, resulting in higher thread strength and avoiding the generation of debris. The plastic deformation of the base metal can prevent the screw with the circular arc triangular cross section from rotating, thus achieving a good anti-loosening effect.
[0020] 3. This utility model has anti-loosening teeth at the screw head, which can be embedded into the hand parts to further enhance the anti-loosening effect. Attached Figure Description
[0021] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0022] Figure 1 A schematic diagram of a self-extruding bolt with self-lubricating function;
[0023] Figure 2 This is a bottom view of a self-extruding bolt with self-lubricating function.
[0024] The diagram shows:
[0025] Screw head 1, Lubricating layer 3
[0026] Screw 2 Anti-loosening tooth 4 Detailed Implementation
[0027] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.
[0028] Example 1
[0029] like Figure 1 and Figure 2 As shown, this embodiment provides a self-extruding bolt with self-lubricating function, including: bolt body, electroplated layer and lubricating layer 3.
[0030] The bolt body includes a screw head 1 and a screw shank 2. The screw head 1 is connected to one end of the screw shank 2, and the screw shank 2 has a threaded structure. An electroplated layer covers the surface of the threaded structure. A lubricating layer 3 covers the electroplated layer and extends from the other end of the screw shank 2 toward the screw head 1. The cross-sectional shape of the threaded structure is a circular arc triangle, and the coverage length of the lubricating layer 3 is greater than or equal to 30% of the total length of the threaded structure. The coverage length of the lubricating layer 3 is less than or equal to 70% of the total length of the threaded structure.
[0031] The electroplated layer is a zinc layer or a zinc-nickel alloy layer. The thickness of the lubricating layer 3 is 0.5mm to 1mm. The lubricating layer 3 is a cured lubricant structure. Anti-loosening teeth 4 are provided at the connection position between the screw head 1 and the screw rod 2. The screw head 1 is a hexagonal head.
[0032] The friction coefficient of the lubricating layer is μ, where μ ≤ 0.07. The tapping torque of the thread structure is M Nm, and the nominal diameter of the thread structure is N mm, where M ≤ 4N.
[0033] The thread structure of this embodiment has a special arc-triangular cross-section to ensure anti-loosening effect after insertion. Its nominal diameter is 12mm, and its insertion torque is tested to be 30Nm. The electroplating layer includes, but is not limited to, electroplated zinc and electroplated zinc-nickel, used to protect the threads from rust. The lubrication layer is formed by applying a lubricant in liquid form to the bolt threads, which then adheres to the bolt after baking, effectively reducing the insertion torque during bolt assembly. Thanks to the good lubrication effect of the lubricant, the bolt has a higher axial force under the same torque, so the anti-loosening teeth can effectively embed into the mating parts, further improving the anti-loosening effect. Through the above methods, the self-extruding bolt provided by this invention is easy to use, has a low insertion torque, good tightening effect, and is highly practical. Figure 1 The horizontal line in the diagram represents the axis of the screw.
[0034] Example 2
[0035] Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1.
[0036] This embodiment provides a high-strength self-extruding bolt, comprising a bolt body, an electroplated layer, and a lubricant. The bolt body includes a screw head and a shank, with an external thread 1 on the shank. The shank has a triangular cross-sectional area, making it less prone to loosening after being driven in. The lubricant is in a solid state, avoiding contamination of transportation and assembly tools. During assembly, it adheres evenly to the threads through compression, effectively reducing the driving torque. The electroplated layer includes, but is not limited to, zinc plating and zinc-nickel alloy plating, and its function is to protect the bolt body from corrosion.
[0037] Furthermore, the lubricant covers the thread starting from the end of the thread. The lubricant coverage length is greater than or equal to 30% of the total thread length.
[0038] Furthermore, the average thickness of the lubricant is 0.5 mm to 1.0 mm.
[0039] Furthermore, the coating is in a fluid state during application and becomes solid after baking, adhering to the threads. The preferred baking temperature is 60-120℃.
[0040] Furthermore, the cured lubricant possesses a certain strength and will not be damaged during bulk packaging and transportation. Areas not covered by the lubricant remain in their clean, initial state, uncontaminated by the lubricant.
[0041] Furthermore, during assembly, the lubricant adheres evenly to all the threads being tapped under the pressure of compression, effectively reducing the tapping torque.
[0042] The purpose of this embodiment is to provide a high-strength self-extruding bolt that has a reasonable structural design, low cost, is easy to use, and has good assembly stability.
[0043] To achieve the above objectives, this embodiment adopts the following technical solution: The high-strength self-extruding bolt of this embodiment includes a screw head and a screw rod. The screw rod is provided with an external thread, which is a 12mm metric thread with an arc-shaped triangular cross-section. After the body is formed, it undergoes electroplating with a zinc-nickel alloy to prevent rust and contamination. After electroplating, a lubricant is applied. The lubricant starts from the end of the thread and covers part or all of the thread. The lubricant is baked and cured, becoming a solid lubricant that adheres to the thread. During assembly, at the thread inlet, the lubricant, under the extrusion action, evenly covers the entire thread, achieving overall lubrication of the thread.
[0044] Furthermore, the lubricant covers 30% to 70% of the thread length.
[0045] The self-tapping screws in this embodiment are easy to use and do not require lubricant before assembly. The solid lubricant evenly covers the threads, effectively reducing frictional torque and providing a stable clamping force. The triangular cross-section threads are driven into the pre-drilled holes in the substrate, and the threads are generated by extrusion, preserving the internal texture of the substrate and resulting in higher thread strength while avoiding the generation of debris. The plastic deformation of the base metal can prevent the screw with the triangular cross-section threads from rotating, achieving a good anti-loosening effect.
[0046] like Figure 1 As shown, the self-extruding bolt provided in this embodiment includes: a bolt body, an electroplated layer, and a lubricant. The bolt body includes a screw head and a shank. An assembly tool acts on the screw head, applying torque to the bolt. Under the action of torque and pressure, the shank penetrates a pre-drilled hole in the substrate and creates threads by extruding the hole wall. During this process, the lubricant on the threads is redistributed throughout all threads. All threads penetrating the substrate are adequately lubricated. Figure 1 As shown, some threads are covered with lubricant, which redistributes under compression, thus ensuring adequate lubrication even for threads not covered with lubricant.
[0047] like Figure 2 As shown, because its thread cross-section is triangular, the assembled bolt is not easy to loosen. Thus, the extremely low coefficient of friction of the lubricant only reduces the approach torque, increases the clamping force, and increases the assembly stability, and does not cause the bolt to loosen easily due to the low coefficient of friction.
[0048] Furthermore, the low coefficient of friction at the threaded part can increase the axial force during tightening, and the anti-loosening teeth can be embedded in the opposite part to enhance the anti-loosening effect.
[0049] This invention provides a lubricating layer at the head of the screw, combined with a thread structure with a circular triangular cross-section and an anti-loosening tooth structure, resulting in a self-extracting bolt with low insertion torque, good tightening effect, and strong practicality.
[0050] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0051] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this utility model. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.
Claims
1. A self-extruding bolt with self-lubricating function, characterized in that, include: The bolt body includes a screw head (1) and a screw rod (2), wherein the screw head (1) is connected to one end of the screw rod (2), and the screw rod (2) is provided with a threaded structure; An electroplated layer covers the surface of the threaded structure; A lubricating layer (3) covers the electroplated layer and extends from the other end of the screw (2) toward the screw head (1); The cross-sectional shape of the threaded structure is a circular arc triangle, and the coverage length of the lubricating layer (3) is greater than or equal to 30% of the total length of the threaded structure.
2. The self-extruding bolt with self-lubricating function according to claim 1, characterized in that, The electroplated layer is a zinc layer or a zinc-nickel alloy layer.
3. The self-extruding bolt with self-lubricating function according to claim 1, characterized in that, The thickness of the lubricating layer (3) is 0.5 mm to 1 mm.
4. The self-extruding bolt with self-lubricating function according to claim 1, characterized in that, The lubricating layer (3) is a cured lubricant structure.
5. The self-extruding bolt with self-lubricating function according to claim 1, characterized in that, The friction coefficient of the lubricating layer is μ, where μ ≤ 0.
07.
6. The self-extruding bolt with self-lubricating function according to claim 1, characterized in that, The tapping torque of the threaded structure is M Nm, the nominal diameter of the threaded structure is N mm, and M≤4N.
7. The self-extruding bolt with self-lubricating function according to claim 1, characterized in that, The connection position between the screw head (1) and the screw rod (2) is provided with anti-loosening teeth (4).
8. The self-extruding bolt with self-lubricating function according to claim 1, characterized in that, The coverage length of the lubricating layer (3) is less than or equal to 70% of the total length of the thread structure.
9. The self-extruding bolt with self-lubricating function according to claim 1, characterized in that, The screw head (1) is a hexagonal head.