Self-locking hexagonal nut

Abstract

The utility model discloses a kind of self-locking hexagonal nut, it is related to fastener technical field.The nut body is divided into upper section, middle section and lower section along axis.The outer side wall of upper section is equipped with through first axial slot, forms first locking petal, and its top end is equipped with taper face close end structure of inner diameter tapering.The outer side wall of middle section is equipped with second axial slot, forms second locking petal, and its inside forms reduced diameter section with inner diameter less than standard thread minor diameter.First and second axial slot are misaligned arrangement.The utility model is through the double-layer different-diameter elastic locking structure of "taper face close end" and "reduced diameter section", when bolt is screwed in, two-stage locking petal can produce collaborative radial compression force, realizes double anti-loosening.The nut is full-metal structure, anti-loosening performance is excellent, can be reused, and is suitable for severe working condition such as vibration, impact.

Description

Technical Field

[0001] This utility model relates to the field of fastener technology, specifically to a reusable hexagonal nut that can maintain high anti-loosening performance under vibration and impact conditions. Background Technology

[0002] Hex nuts, as one of the most basic mechanical fasteners, are widely used in various equipment and structures. However, under conditions of long-term vibration, impact, or alternating loads (such as in rail transportation, heavy machinery, wind power generation, etc.), ordinary hex nuts will gradually loosen due to microscopic slippage between the threaded parts, resulting in a decrease in preload, connection failure, and even serious safety accidents.

[0003] To address this issue, existing technologies have proposed various anti-loosening nut solutions, but all of them have certain limitations: Nylon insert nuts: These nuts use the reduced inner diameter of the nylon ring to create an interference fit with the bolt to prevent loosening. However, they have poor high-temperature resistance, and the nylon ring is prone to wear, limiting their reusability. They are not suitable for high-temperature, high-reliability applications.

[0004] Double-nut tightening: This method prevents loosening by tightening two nuts together. This increases installation space and weight, and its effectiveness depends on the correct installation torque; there is still a risk of loosening under strong vibration.

[0005] All-metal lock nuts (such as single-layer slotted nuts): These nuts utilize elastic deformation to generate radial locking force by creating an axial groove at one end and crimping it closed. However, these nuts typically have only one locking point, resulting in limited anti-loosening capability. Furthermore, their elasticity tends to diminish after repeated disassembly and assembly, leading to a significant decrease in locking performance.

[0006] Adhesive-coated nuts: These are nuts with anaerobic adhesive or other chemical adhesives applied to their threads. Their anti-loosening effect is greatly affected by the quality and cleanliness of the adhesive, and they are for single use only, making maintenance and replacement inconvenient.

[0007] In summary, existing anti-loosening nuts are either limited by material properties, have complex structures and high costs, or lack reliable anti-loosening capabilities and are not reusable. Summary of the Invention

[0008] In order to overcome the above-mentioned defects of the prior art, the present invention aims to provide a self-locking anti-loosening hexagonal nut with simple structure, excellent anti-loosening performance and reusability.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A self-locking anti-loosening hexagonal nut includes a nut body, which is a hexagonal prism with a through threaded hole in its middle. The nut body includes an upper section, a middle section, and a lower section arranged coaxially along its axis. The outer wall of the upper section has several first axial grooves penetrating its upper end face, which divide the upper section into several independent first locking flaps. The inner threaded hole of the upper section has a tapered constriction structure with the large end facing upward and the small end facing downward, and its inner diameter gradually decreases from the upper end face of the nut to the inside of the nut. The outer wall of the middle section has several second axial grooves, which divide the middle section into several independent second locking flaps. The inner threaded area enclosed by the second locking flaps is a reduced diameter section, the inner diameter of which is smaller than the standard minor diameter of the threaded hole. The first axial grooves and the second axial grooves are staggered in the circumferential direction of the nut.

[0010] Preferably, the height of the conical constriction structure is less than the axial height of the first locking flap.

[0011] Preferably, the inner diameter of the small end outlet of the conical constriction structure is larger than the inner diameter of the constriction section.

[0012] Preferably, the number of the first axial groove and the second axial groove are both 4 to 8, and they are evenly distributed along the circumference.

[0013] Preferably, the offset angle between the first axial groove and the second axial groove is 15° to 45°.

[0014] Preferably, the lower section is a complete hexagonal prism, and its internal thread and bolt are in clearance fit.

[0015] Preferably, the nut body is made of a metal material with elasticity and strength, such as spring steel, alloy steel, or copper alloy.

[0016] This utility model has the following advantages compared with the prior art: 1. Double locking for high reliability: This utility model creatively sets up a two-stage locking structure of "conical constriction" and "diameter reduction section". When the bolt is screwed in, it is subjected to radial clamping forces from two different positions generated by the upper conical structure and the middle diameter reduction structure, forming a synergistic double anti-loosening barrier. The anti-loosening effect is far superior to that of a nut with single-point locking.

[0017] 2. All-metal structure with wide applicability: The nut is made entirely of metal, which is resistant to high temperature, aging, and corrosion, and can be used in various harsh working conditions, solving the environmental limitations of nylon insert nuts.

[0018] 3. Reusable and economical: The deformation of all locking valves is within the elastic limit of the material. They can be restored to their original shape after disassembly. The locking performance will not be significantly reduced due to repeated disassembly and assembly. It has a long service life and low maintenance cost.

[0019] 4. Simple structure and easy to manufacture: This nut can be mass-produced through standard processes such as cold heading and machining. It only adds grooving and local internal hole forming processes to the existing nut, which makes the cost controllable and easy to promote.

[0020] 5. Staggered design for uniform stress distribution: The first and second locking plates are staggered, which makes the radial locking force evenly applied to different circumferential positions of the bolt thread, avoiding stress concentration and ensuring the stability of the connection and the service life of the bolt. Attached Figure Description

[0021] Figure 1 Main view (section view); Figure 2 This is a magnified view of point A; Figure 3 This is an overall top view; Figure 4 This is a top view of BB.

[0022] In the diagram: 1-Nut body; 11-Upper section; 12-Middle section; 13-Lower section; 2-Threaded hole; 3a-First axial groove; 3b-Second axial groove; 4a-First locking flap; 4b-Second locking flap; 5-Contraction structure; 6-Reduced diameter section; H1-Conical surface height; H2-First locking flap height; D1-Small end outlet inner diameter; D2-Reduced diameter section inner diameter; D3-Standard minor diameter of threaded hole. Detailed Implementation

[0023] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments of this utility model, so that those skilled in the art can fully understand and implement it.

[0024] like Figures 1 to 4 As shown, this embodiment provides a self-locking anti-loosening hexagonal nut, including a nut body 1. The nut body 1 is a standard external hexagonal shape, and a standard metric threaded hole 2 is machined inside. The nut body 1 is divided into three functional sections along the axial direction: upper section 11, middle section 12, and lower section 13.

[0025] Six first axial grooves 3a are uniformly machined along the outer wall of the upper section 11, penetrating its upper end face. These grooves divide the upper section 11 into six independent, elastic first locking flaps 4a. At the top of the upper section 11, i.e., at the entrance of the threaded hole 2, a conical constriction structure 5 is machined. The larger end of this conical surface faces upward to facilitate bolt insertion; the smaller end faces downward, and its inner diameter D1 is slightly smaller than the standard minor diameter D3 of the thread. The height H1 of the conical constriction structure 5 is less than the height H2 of the first locking flaps 4a.

[0026] Six second axial grooves 3b are also uniformly machined on the outer wall of the middle section 12. These grooves are staggered by 30° from the first axial groove 3a in the circumferential direction, thereby dividing the middle section 12 into six independent second locking flaps 4b. The inner hole enclosed by these six second locking flaps 4b is machined into a reduced diameter section 6, the inner diameter D2 of which is smaller than the standard minor diameter D3 of the threaded hole 2, and also smaller than the small end outlet inner diameter D1 of the tapered constriction structure 5.

[0027] The lower section 13 is a complete hexagon with a standard internal thread, which mainly serves as a guide and ultimately bears the load.

[0028] During installation, the bolt is first screwed into the tapered constriction structure 5. As the inner diameter of the tapered surface gradually decreases from top to bottom, the bolt thread forces the first locking flap 4a to elastically expand outward, generating the first radial preload. As the bolt continues to screw in, when it reaches the reduced-diameter section 6 of the middle section 12, the bolt thread must overcome greater resistance to pass through due to the even smaller inner diameter. This causes the second locking flap 4b to expand more significantly, generating a second, stronger, and deeper radial locking force. Ultimately, the bolt's threaded section is tightly held by two elastic pressure points of different heights and staggered angles, creating an extremely reliable anti-loosening effect. During disassembly, the bolt is unscrewed in the opposite direction; the two locking flaps recover elastically without damaging the threads, allowing for reuse.

[0029] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technical principles and solutions disclosed in this utility model, based on the technical solutions and inventive concepts of this utility model, should be included within the protection scope of this utility model.

Claims

1. A self-locking anti-loosening hexagonal nut, comprising a nut body (1), wherein the nut body (1) has a through threaded hole (2) in the middle, characterized in that: The nut body (1) includes, along its axial direction, an upper section (11), a middle section (12), and a lower section (13) arranged coaxially. The outer wall of the upper section (11) has several first axial grooves (3a) penetrating its upper end face. These first axial grooves (3a) divide the upper section (11) into several independent first locking flaps (4a). The internal threaded opening at the top of the upper section (11) has a tapered constriction structure (5), with its large end facing upwards and its small end facing downwards. Its inner diameter extends from the nut... The upper end gradually decreases in the direction facing the inside of the nut; the outer wall of the middle section (12) is provided with several second axial grooves (3b), the second axial grooves (3b) divide the middle section (12) into several independent second locking flaps (4b); the internal thread area enclosed by the second locking flaps (4b) is a reduced diameter section (6), the inner diameter of the reduced diameter section (6) is smaller than the standard thread minor diameter of the threaded hole (2); the first axial groove (3a) and the second axial groove (3b) are staggered at an angle in the circumferential direction of the nut.

2. The self-locking anti-loosening hexagonal nut according to claim 1, characterized in that: The height of the conical constriction structure (5) is less than the height of the first locking flap (4a).

3. The self-locking anti-loosening hexagonal nut according to claim 2, characterized in that: The inner diameter (D1) of the small end outlet of the tapered conical constriction structure (5) is greater than the inner diameter (D2) of the constriction section (6).

4. The self-locking anti-loosening hexagonal nut according to claim 1, characterized in that: The number of the first axial groove (3a) and the second axial groove (3b) are both 4 to 8, and they are evenly distributed along the circumference.

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