A reinforced fastener and a device containing the reinforced fastener

Abstract

This utility model belongs to the field of fastener technology, specifically relating to a reinforced fastener and a device containing the reinforced fastener. The reinforced fastener includes, along its axial direction, a screw body, a flange, a stepped body, and a drive end. The screw body is a cylindrical rod with external threads machined on its outer surface for mating with threaded holes in the components to be connected. The flange is disc-shaped and coaxially connected to the end of the screw body. The stepped body connects the flange to the cylindrical drive end, with the radial dimensions of the flange, stepped body, and drive end decreasing sequentially. The drive end has a ring-shaped array of meshing teeth integrally formed with it, each meshing tooth having a semi-circular cross-section. This fastener effectively improves torque transmission stability, reduces end shear and tooth root cracking, has high torsional load-bearing capacity, and is suitable for applications such as wind turbine nacelle shells, aerospace equipment frame profiles, and electric vehicle drive unit shell connections.

Description

Technical Field

[0001] This utility model belongs to the field of fastener technology, specifically relating to a reinforced fastener and a device containing the reinforced fastener. Background Technology

[0002] Fasteners are core components in mechanical engineering, enabling the connection and fixation of parts. Their applications cover almost all industrial sectors, including automobile manufacturing, aerospace, construction machinery, wind power equipment, rail transportation, and high-precision instruments. During the assembly and operation of various equipment, fasteners not only provide positioning and connection between components, but their connection stability, load-bearing capacity, and failure resistance directly determine the safety, reliability, and long-term service life of the entire structure, making them crucial fundamental components for ensuring the normal operation of equipment.

[0003] With the continuous upgrading of modern industrial technology, various equipment is developing towards larger size, higher precision, higher load capacity, and longer service life, which places more stringent requirements on the performance of fasteners. On the one hand, the complex operating conditions such as vibration, impact, and alternating loads faced by equipment during operation require fasteners to have stronger fastening reliability to avoid safety hazards caused by loose connections. On the other hand, in the pursuit of lightweight and compact equipment, fasteners need to achieve higher torsional load capacity and damage resistance within limited size specifications to meet the fastening requirements in high-load scenarios. Therefore, continuously improving the mechanical properties of fasteners and enhancing their reliability is not only an important aspect of optimizing the overall performance of equipment, but also a practical need to drive technological progress in related industrial fields.

[0004] Although fastener technology has matured relatively quickly over time, and the market offers a range of national standard products covering different end types and thread specifications to meet basic connection needs under general working conditions, further optimization of fastener performance remains crucial in the face of increasingly stringent reliability requirements from high-end equipment. For example, given the limited structural dimensions of fasteners, design improvements to reduce the risk of failure caused by localized overloads, while simultaneously enhancing torsional load-bearing capacity, represent real challenges to fastener technology as the industry moves towards high-end applications. Utility Model Content

[0005] In view of the shortcomings of the existing technology, this utility model provides a reinforced fastener and a device containing the reinforced fastener.

[0006] The purpose of this utility model is to provide a high-performance fastener that is easy to manufacture and can be adapted to the high load and high reliability requirements of high-end equipment, while also having good practicality and economy, thereby promoting the technological iteration and application expansion of fastener products and helping the industry achieve high-end upgrading.

[0007] The reinforced fastener of this utility model includes, in sequence along the axial direction, a screw body, a flange, a stepped body, and a drive end. The screw body is a cylindrical rod with external threads machined on its outer surface for mating with the threaded holes of the component to be connected. The flange is disc-shaped and coaxially connected to the end of the screw body. The stepped body connects the flange to the cylindrical drive end, and the radial dimensions of the flange, the stepped body, and the drive end decrease sequentially. The drive end has a ring array of meshing teeth integrally formed with the drive end. Each meshing tooth has a semi-circular cross-section and extends axially to the stepped body, forming a semi-cylindrical structure. There are 5 meshing teeth, which are evenly distributed at 72° intervals along the circumference of the drive end.

[0008] As a further optimization, a transition filler is integrally provided at the junction of the drive end and the step body, and between the adjacent meshing teeth on the periphery, with the exposed surface of the transition filler being sloped.

[0009] As a further optimization scheme, the exposed surface on the periphery of the drive end is a circular arc cylindrical surface. Let the radius of the exposed circular arc cylindrical surface of the drive end be R1, and the radius of the meshing teeth be R2. R1 and R2 satisfy R1 / R2=2.45~3.25.

[0010] As a further optimization scheme, R1 and R2 satisfy R1 / R2 = 2.75~3.10.

[0011] As a further optimization solution, the screw body, flange, stepped body, drive end, meshing teeth, and transition filler are integrally molded structures.

[0012] As a further optimization, the exposed surface of the transition filler is a partially conical surface.

[0013] This utility model also provides a device containing a reinforced fastener, including at least two components to be connected, and at least one reinforced fastener for connecting the components to be connected; the reinforced fastener is any of the above-mentioned reinforced fasteners; the screw body of the reinforced fastener passes through the mounting holes of the two components to be connected, the external thread on the outer surface of the screw body engages with the thread on the inner wall of the mounting hole of one of the components to be connected, and the end face of the flange away from the step body abuts against the surface of the other component to be connected, so as to achieve a fixed connection between the two components to be connected.

[0014] As a further optimization, reinforced fasteners are made of 6000 series aluminum alloy, titanium alloy or high-strength steel in one piece.

[0015] As a further optimization, the device can be any one of the following: a wind turbine, wherein the nacelle shells of the wind turbine are connected by reinforced fasteners; an aerospace device, wherein the frame profiles of the aerospace device are connected by reinforced fasteners; or an electric vehicle drive unit, wherein the drive housings of the electric vehicle drive unit are connected by reinforced fasteners.

[0016] Beneficial effects

[0017] This new type of reinforced fastener achieves a stable connection with the connected components, improves torque transmission stability during tightening, reduces the risk of structural damage during tightening, and minimizes end shear failure and tooth root cracking. Its torsional load-bearing capacity is significantly improved compared to standard fasteners of the same material and size, meeting the needs of fastening applications with higher load requirements. Its excellent connection reliability, torsional performance, and failure resistance make it suitable for applications with stringent requirements for connection stability, load-bearing capacity, and long-term service performance, such as wind turbine nacelle shells, aerospace equipment frame profiles, and electric vehicle drive unit shells. In these scenarios, it effectively resists the influence of complex working conditions such as vibration and alternating loads, ensuring the long-term stability of the component connection. Attached Figure Description

[0018] Figure 1 This is a three-dimensional schematic diagram of the reinforced fastener of this utility model.

[0019] Figure 2 This is a top view of the reinforced fastener of this utility model.

[0020] Figure 3 This is a cross-sectional schematic diagram of the end of the reinforced fastener of this utility model.

[0021] Figure 4 This is a cross-sectional schematic diagram of the national standard hexagonal plum blossom E-type end structure.

[0022] Figure 5 This is a stress distribution diagram obtained from simulation calculations of the reinforced fastener specimen of this utility model.

[0023] Figure 6 The stress distribution diagram is obtained from the simulation calculation of the national standard fastener specimen.

[0024] Figure 7 The graph shows the torque variation with torsion angle obtained from the simulation calculation of the reinforced fastener specimen of this utility model.

[0025] Figure 8 The graph shows the torque variation with torsion angle obtained from simulation calculations of national standard fastener specimens.

[0026] In the figure, 1 is the screw body; 2 is the flange; 3 is the stepped body; 4 is the drive end; 5 is the meshing teeth; and 6 is the transition filler. Detailed Implementation

[0027] The present invention is further illustrated by the following embodiments, which are intended to more clearly illustrate the technical solution of the present invention, and should not be construed as a limitation.

[0028] The fastener structure of this utility model is as follows: Figure 1 and Figure 2 As shown, the device includes a screw body 1, a flange 2, a stepped body 3, and a drive end 4 in sequence along the axial direction. The drive end 4 is provided with meshing teeth 5 around its periphery, and a transition filler 6 is further provided at the junction of the drive end 4 and the stepped body 3.

[0029] Among them, the screw body 1 is a cylindrical rod with external threads machined on its outer surface. These external threads are used to mate with the threaded holes on the components to be connected, thereby providing a basic connection function for the fastener and ensuring that the components to be connected can be stably joined.

[0030] The flange 2 is located at one end of the screw body 1, and is disc-shaped, coaxial with the screw body 1 and integrally formed. The flange 2 can increase the axial support area between the fastener and the connecting surface. On the one hand, it can help to achieve positioning during the fastener installation process and ensure the accuracy of the installation position. On the other hand, it can effectively disperse the pressure of the fastener on the connecting surface and avoid the connecting surface from being crushed due to excessive local pressure, thereby protecting the connecting surface.

[0031] The step body 3 is connected between the flange 2 and the drive end 4. It is coaxial with both and integrally connected. Its diameter is smaller than that of the flange 2, thus forming a step transition structure between the flange 2 and the drive end 4, which facilitates the structural layout and processing of the drive end 4.

[0032] The drive end 4 is the main body of the head, roughly cylindrical in shape, coaxial with and integrally connected to the step body 3, located on the side of the step body 3 away from the flange 2, and is used to cooperate with the drive tool to provide a force application point for the drive tool so that the drive tool can apply torque to the fastener to realize the tightening or loosening operation of the fastener.

[0033] On the peripheral side of the drive end 4, a ring array of meshing teeth 5 is distributed, and the meshing teeth 5 are integrally formed with the drive end 4. In this embodiment, as shown... Figure 3As shown, the meshing teeth 5 are preferably arranged in a configuration of 5 teeth, each meshing tooth 5 being evenly distributed at 72-degree intervals along the circumference of the drive end 4; the cross-section of each meshing tooth 5 is semi-circular, and each meshing tooth 5 extends axially to the step body 3, forming a roughly semi-cylindrical shape; the radius of the drive end 4 is R1, the radius of the meshing tooth 5 is R2, and R1 / R2 = 2.45~3.25. This structure differs from the hexagonal plum blossom E-type structure specified in conventional national standards (such as GB6189-86 "Hexagonal Flower-Type Fasteners - E-type"), such as... Figure 4 As shown, it has 6 teeth with different tooth profiles. These 5 semi-circular cross-section meshing teeth 5 enhance the meshing reliability with the drive tool sleeve hole, reduce slippage during the driving process, and improve the stability of torque transmission, significantly increasing the torque-bearing capacity of the fastener. In addition, at the junction of the drive end 4 and the step body 3, and between adjacent meshing teeth 5 on the periphery, a transition filler 6 is integrally provided. The exposed surface of the transition filler 6 is sloped, specifically a partial conical surface. The provision of the transition filler 6 can, on the one hand, strengthen the connection strength between the drive end 4 and the step body 3, and prevent shearing damage to the connection surface between the drive end 4 and the step body 3 due to torque when tightening the fastener (i.e., the root of the drive end 4 is broken off). On the other hand, it can also stabilize the meshing teeth 5, preventing damage to the meshing teeth 5 or detachment from the drive end 4 under torque (i.e., "stripping"), further ensuring the reliability of the meshing transmission between the meshing teeth 5 and the drive tool.

[0034] Through the synergistic effect of the above-mentioned screw body 1, flange 2, step body 3, drive end 4, meshing teeth 5, and transition filler 6, the fastener of this utility model can not only achieve a reliable connection function, but also optimize and improve the stability of drive meshing and the torsional strength of the structure, effectively improving the problems of end shearing damage and meshing tooth damage that are most likely to occur in conventional fasteners.

[0035] To further verify the torsional bearing capacity of the reinforced fastener drive end of this utility model, a simulation experiment was conducted using the national standard fastener structure as a benchmark. The differences in mechanical properties between the two under the same working conditions were compared and analyzed. 6056-T6 aluminum alloy was used as the specimen material in the experiment. The mechanical property parameters of this material are: tensile strength 425 MPa, yield strength 380 MPa. Two sets of test pieces were set up for the experiment. The materials and overall dimensions were strictly controlled to be consistent, and the differences were only made by the tooth shape and structural design of the drive end. Among them, the drive end radius R1 of the test piece of this utility model is 4.92mm, the meshing tooth radius R2 is 1.75mm, and the R1 / R2 ratio is about 2.81, which is within the optimal design range of 2.45~3.25. Its meshing tooth structure consists of 5 semi-circular cross-section teeth evenly distributed along the circumference at 72°, and the tooth part extends axially to the step body, and is equipped with a transition filler 6. The control test piece adopts the E14 wrench end conforming to the GB6189-86 "Hexagonal Flower-Type - E-type Fasteners" standard, which has 6 meshing teeth and the tooth shape follows the standard specifications.

[0036] The experiment was conducted using the finite element method (FEM) simulation analysis. The specific procedure is as follows: First, based on the determined specimen parameters, two sets of three-dimensional solid models of the specimens were constructed, along with wrench sleeves that corresponded to the wrench end shapes of the specimens. Then, boundary conditions conforming to the actual wrenching conditions of the fasteners were set, namely, fixing the screw body 1 and restricting its axial, radial, and circumferential displacements. A torsional load along the specimen axis was applied to the drive end 4 through the wrench sleeves, and the actual torque loading process was simulated by gradually increasing the torsion angle. Analysis indicators included the Mises equivalent stress distribution (used to assess stress concentration and structural stress rationality) and the torque-torsion angle curve (used to assess torsional performance and extract the maximum torsional torque). The mechanical response data of the two sets of specimens during the loading process were recorded using the simulation system.

[0037] After the simulation experiment was completed, the mechanical response data of the two sets of specimens were collected and compared for analysis: in terms of stress distribution, Figure 5 This is the Mises equivalent stress distribution diagram of the specimen of this utility model. Figure 6 To compare the Mises equivalent stress distribution diagrams of the specimens, it is evident that the comparative specimen exhibits more pronounced stress concentration and localized torsion, with the maximum stress concentrated on a localized tooth surface on the outer periphery of the drive end. In contrast, the stress distribution of the specimen of this invention is more uniform and dispersed. Regarding torsional bearing capacity... Figure 7 This is the torque-torsion angle variation curve of the specimen of this utility model. Figure 8To compare the torque-torsional angle variation curves of the specimens, both sets of curves showed a trend of initial linear growth (elastic deformation stage, where torque is proportional to torsional angle), followed by a nonlinear stage (plastic deformation stage, where the rate of torque growth slows down), and finally reaching the peak torque (the maximum torque before the specimen loses its load-bearing capacity). The specimen of this invention exhibits a larger linear range, with a maximum torsional torque of 108 Nm, while the maximum torsional torque of the comparative specimen is 95 Nm. The maximum torsional torque of the specimen of this invention is approximately 13.7% higher than that of the comparative specimen, verifying the significant advantage of this invention in torsional load-bearing capacity.

[0038] In summary, the drive end structure of the reinforced fastener of this invention can effectively optimize the stress distribution and reduce the stress concentration, thereby reducing the risk of common failures such as end shear failure and tooth root cracking. At the same time, its maximum torsional torque is significantly improved compared with the national standard structure of the same size, and its torsional bearing capacity is significantly enhanced, which can meet the fastening application scenarios with higher load requirements.

[0039] The above embodiments are exemplary and are intended to illustrate the technical concept and features of this utility model, so that those skilled in the art can understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A reinforced fastener, characterized in that, The device comprises, in sequence along the axial direction, a screw body (1), a flange (2), a stepped body (3), and a drive end (4); the screw body (1) is a cylindrical rod with external threads machined on its outer surface for mating with the threaded holes of the component to be connected; the flange (2) is disc-shaped and coaxially connected to the end of the screw body (1); the stepped body (3) connects the flange (2) and the cylindrical drive end (4), and the radial dimensions of the flange (2), the stepped body (3), and the drive end (4) decrease sequentially; the drive end (4) has a ring array of meshing teeth (5) integrally formed with the drive end (4); the cross-section of each meshing tooth (5) is semi-circular, and each meshing tooth (5) extends axially to the stepped body (3) to form a semi-cylindrical structure; the number of meshing teeth (5) is 5, and each meshing tooth (5) is evenly distributed at 72° intervals along the circumference of the drive end (4).

2. The reinforced fastener according to claim 1, characterized in that, The drive end (4) and the step body (3) are connected at the junction and between the adjacent meshing teeth (5) on the periphery, and a transition filler (6) is integrally provided. The exposed surface of the transition filler (6) is sloped.

3. The reinforced fastener according to claim 1, characterized in that, The exposed surface of the drive end (4) is a cylindrical arc surface. Let the radius of the exposed cylindrical arc surface of the drive end (4) be R1, and the radius of the meshing tooth (5) be R2. R1 and R2 satisfy R1 / R2=2.45~3.

25.

4. The reinforced fastener according to claim 3, characterized in that, The values ​​of R1 and R2 satisfy R1 / R2 = 2.75~3.

10.

5. The reinforced fastener according to claim 1, characterized in that, The screw body (1), flange (2), step body (3), drive end (4), meshing teeth (5) and transition filler (6) are integrally formed structures.

6. The reinforced fastener according to claim 2, characterized in that, The exposed surface of the transition filler (6) is a partially conical surface.

7. A device containing reinforced fasteners, characterized in that, It includes at least two components to be connected, and at least one reinforcing fastener for connecting the components to be connected; the reinforcing fastener is a reinforcing fastener as described in any one of claims 1-6; the screw body (1) of the reinforcing fastener passes through the mounting holes of the two components to be connected, the external thread on the outer surface of the screw body (1) is threaded with the inner wall of the mounting hole of one of the components to be connected, and the end face of the flange (2) away from the step body (3) abuts against the surface of the other component to be connected, so as to achieve a fixed connection between the two components to be connected.

8. The device with reinforced fasteners according to claim 7, characterized in that, The reinforced fastener is made of 6000 series aluminum alloy, titanium alloy or high-strength steel in one piece.

9. The device with reinforced fasteners according to claim 7, characterized in that, The device is any one of the following: The device is a wind power equipment, and the nacelle shell of the wind power equipment is connected by the aforementioned reinforced fasteners; The device is an aerospace equipment, and the frame profiles of the aerospace equipment are connected by the aforementioned reinforced fasteners; The device is an electric drive unit for an electric vehicle, and the electric drive housings of the electric drive unit are connected by the aforementioned reinforced fasteners.

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