A pin riveting lock bolt assembly and method of assembly

Abstract

The application discloses a pin-riveting anti-loose bolt assembly and an assembling method. The assembly comprises a bolt body, an anti-loose nut and a locking washer. The rod part of the bolt body is sequentially provided with a fine thread segment, a trapezoidal thread segment and a terminal positioning groove. The anti-loose nut is provided with an inner thread matched with the fine thread segment, an internal anti-loose thread engaged with the trapezoidal thread segment and a positioning boss matched with the terminal positioning groove. The assembling method comprises a bolt mounting step, a nut screwing step and a pin-riveting fixing step. During the assembling, the positioning boss and the terminal positioning groove form an interference fit structure limiting. Then, in the pin-riveting fixing step, axial pressure is applied to the anti-loose nut, so that the internal anti-loose thread and the engagement surface of the trapezoidal thread segment are plastically deformed to form permanent locking. The application solves the problem that the prior art is prone to loosening under high-vibration working conditions by the triple anti-loose mechanism of mechanical locking, structural limiting and plastic locking, and improves the reliability, strength and fatigue life of the connection.

Description

Technical Field

[0001] This application relates to the field of high-strength fasteners and riveting technology, specifically to a pin-riveted anti-loosening bolt assembly and assembly method. This assembly and method are particularly suitable for connecting metal components under high vibration and high load conditions, such as automobile beams, high-speed railway bridge main structures, and wind turbine tower flanges, especially in scenarios requiring long-term resistance to alternating loads. Background Technology

[0002] In modern industrial manufacturing, the connection of high-strength components is a crucial link in ensuring the safety and reliability of the overall structure. Currently, the mainstream connection methods mainly include traditional bolt and nut connections, riveting connections, and various improved anti-loosening bolt connections.

[0003] Traditional bolt and nut connections rely primarily on the friction generated by the preload applied between the threaded pairs to prevent loosening. However, under conditions of high-frequency vibration or continuous alternating loads, the microscopic relative motion between the threaded pairs causes the preload to gradually decrease, leading to a reduction in friction and ultimately loosening of the connection. Experimental data shows that after prolonged fatigue testing, the loosening rate of traditional bolt connections can reach over 35%, posing a serious safety hazard.

[0004] Rivet connections fill workpiece holes and achieve permanent fixation through plastic deformation of the rivet shank. Their advantages include simple structure and low cost. However, under continuous vibration loads, micro-gaps can easily form between the rivet shank and the hole wall due to material fatigue, leading to decreased connection tightness and loosening. Furthermore, the shear strength of traditional rivets is typically between 80-120 MPa, which is insufficient for the long-term use requirements of heavy equipment such as wind turbine towers that need to withstand shear loads exceeding 150 MPa.

[0005] To address these issues, the industry has developed various anti-loosening bolt technologies, such as toothed washers, spring washers, or anti-loosening adhesives. While these technologies improve anti-loosening performance to some extent, their essence remains the same: enhancing or maintaining friction. For example, toothed washers increase frictional resistance by embedding teeth into the connection surface, but their meshing area is limited, and the teeth are easily worn down under high-intensity loads, weakening the anti-loosening effect over time.

[0006] Furthermore, existing connection technologies also have shortcomings in their assembly processes. During manual or conventional mechanical assembly, the lack of precise positioning and guiding structures often results in coaxiality errors between the bolts and workpiece holes exceeding 0.5mm. This assembly deviation leads to uneven load distribution at the connection interface, creating localized stress concentrations and significantly reducing the fatigue life of the connection structure. Simultaneously, loose connections also incur high maintenance costs; for infrastructure such as high-speed railway bridges and large wind power equipment, the cost of a single downtime for maintenance is extremely high.

[0007] Therefore, how to provide a fastener technology that can guarantee extremely high connection strength and assembly accuracy while fundamentally overcoming the problem of frictional attenuation and achieving long-term, reliable anti-loosening is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] The main objective of this application is to provide a pin-riveted anti-loosening bolt assembly and assembly method to solve the technical problems in the prior art, such as the easy loosening and insufficient reliability of bolted connections under high-frequency vibration conditions, as well as the limited strength and low assembly accuracy of traditional riveting.

[0009] To achieve the above objectives, the first aspect of this application provides a pin-fitted anti-loosening bolt assembly, including a bolt body, an anti-loosening nut, and a locking washer;

[0010] The bolt body has a fine thread section, a trapezoidal tooth section and an end positioning groove in sequence along its axial direction.

[0011] The anti-loosening nut has an internal thread that mates with the fine thread section, and the inner hole of the anti-loosening nut is also provided with internal anti-loosening teeth that mesh with the trapezoidal tooth section. Furthermore, a positioning boss that mates with the end positioning groove is provided on the end face facing the head side of the bolt body.

[0012] Wherein, after the anti-loosening nut is assembled with the bolt body, the positioning boss and the end positioning groove form an interference fit, and the internal anti-loosening teeth and the trapezoidal toothed section undergo plastic deformation under axial pressure to form a permanent locking structure.

[0013] In a preferred embodiment, the head end face of the bolt body is provided with a press-fit positioning hole. The press-fit positioning hole is a cylindrical blind hole with its axis coinciding with the central axis of the bolt body. It is used to cooperate with the positioning pin of the external tooling during assembly to ensure that the coaxiality error of the assembly is less than or equal to 0.1mm.

[0014] In a preferred embodiment, the positioning boss is an annular boss circumferentially arranged around the inner hole of the lock nut, and the end positioning groove is a circumferential groove circumferentially arranged around the shank of the bolt body; the outer diameter of the positioning boss in the free state... Larger than the inner diameter of the end positioning groove in its free state The two form an over-compensation pair, and the amount of over-compensation... The range is configured to be from 0.02mm to 0.05mm.

[0015] In a preferred embodiment, the trapezoidal toothed segment has an asymmetrical trapezoidal tooth shape, and the angle between its bearing tooth surface and the normal plane perpendicular to the bolt body axis is... Smaller than the angle between its non-load-bearing tooth surface and the normal plane. The included angle The range is 5° to 10°, the included angle The range is 40° to 50°; the tooth shape of the internal anti-loosening tooth pattern matches the tooth shape of the trapezoidal tooth pattern segment. This asymmetrical structure causes stress to concentrate on the bearing tooth surface when axial pressure is applied, and induces it to undergo directional and controllable plastic deformation.

[0016] In a preferred embodiment, the outer contour of the lock nut is a dodecagonal structure, which is used to cooperate with a dodecagonal socket tool to apply a precise and stable preload torque.

[0017] The second aspect of this application provides a method for assembling a pin-mounted anti-loosening bolt, the pin-mounted anti-loosening bolt comprising a bolt body and an anti-loosening nut, the shank of the bolt body having a trapezoidal toothed section and an end positioning groove, and the head having a press-fit positioning hole, the anti-loosening nut having internal anti-loosening teeth that engage with the trapezoidal toothed section and a positioning boss that mates with the end positioning groove; the method includes the following steps:

[0018] The bolt installation steps involve inserting the positioning pin of the press-fitting fixture into the press-fitting positioning hole and pressing the bolt body coaxially into the workpiece.

[0019] In the nut tightening step, the anti-loosening nut is screwed into the bolt body until the positioning boss and the end positioning groove are engaged, and the internal anti-loosening teeth are fully engaged with the trapezoidal tooth segment;

[0020] In the pin-riveting fixing step, a preset axial pressure is applied to the tightened anti-loosening nut, causing plastic deformation of the meshing surface between the internal anti-loosening teeth and the trapezoidal tooth segment.

[0021] In a preferred embodiment, during the bolt installation step, by precisely engaging the locating pin with the press-fit locating hole, the bolt body is pressed into the preset mounting hole of the workpiece, and the coaxiality error between the central axis of the bolt body and the central axis of the preset mounting hole is less than or equal to 0.1 mm.

[0022] In a preferred embodiment, during the pin-fixing step, the preset axial pressure The size is based on the material yield strength of the trapezoidal toothed segment. Effective bearing area of ​​tooth meshing The predetermined axial pressure Satisfying mathematical relations This ensures that the meshing surface stably enters the plastic deformation region, while avoiding macroscopic fracture of the material due to excessive pressure.

[0023] In a preferred embodiment, the plastic deformation is a micro-indentation of controllable depth formed on the bearing tooth surface of the internal anti-loosening teeth and the trapezoidal tooth segment. This plastic deformation causes dislocations and slippage in the surface lattice of the bearing tooth surface, resulting in a work hardening effect; the depth of the plastic deformation... Precisely controlled within the range of 0.01mm to 0.03mm, this depth is sufficient to completely eliminate manufacturing tolerances and fit clearances between tooth surfaces to form irreversible mechanical locking, while avoiding excessive stress concentration at the tooth root, thus ensuring the long-term fatigue resistance of the connection structure under high-frequency alternating loads.

[0024] In a preferred embodiment, during the nut tightening step, a special dodecagonal socket tool is used to apply a preload torque to the lock nut, which has a dodecagonal outer contour.

[0025] Compared with the prior art, this application has the following beneficial effects:

[0026] This application utilizes the synergistic effect of a triple anti-loosening mechanism—"mechanical toothed locking," "structural limiting," and "plastic deformation locking"—to transform the traditional friction-based anti-loosening method into an irreversible mechanical structural locking system, resulting in high anti-loosening reliability. Even under vibration conditions with frequencies up to 100Hz and accelerations up to 5g, it can achieve long-term stability without loosening, reducing the connection loosening rate to 0%.

[0027] This component is made of high-strength alloy steel, and the plastic deformation locking eliminates meshing gaps, resulting in a connection shear strength of over 200 MPa, far exceeding that of traditional bolts and rivets. High-precision coaxial assembly effectively avoids localized stress concentration, thus extending the fatigue life of the connection several times compared to traditional bolts.

[0028] The press-fit positioning holes on the bolt heads, in conjunction with specialized tooling, allow for precise control of assembly coaxiality errors to within 0.1mm. This high-precision assembly ensures uniform load distribution across the connection interface, forming the basis for improving the structure's fatigue resistance and reliability.

[0029] The standardized positioning, tightening, and axial pressing steps are easy to integrate into automated production lines and can be performed by robots, improving assembly efficiency and quality consistency while reducing labor costs. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a structural block diagram of a pin-riveting anti-loosening bolt assembly provided in an embodiment of the present invention.

[0032] Figure 2 This is a flowchart of a pin-riveting anti-loosening bolt assembly method provided in an embodiment of the present invention.

[0033] Figure 3 This is a cross-sectional view of the assembled state of the pin-riveting anti-loosening bolt assembly provided in an embodiment of the present invention, wherein 2 and 3 are the connected workpieces.

[0034] Figure 4 This is an exploded disassembly diagram of the anti-loosening bolt assembly provided in an embodiment of the present invention.

[0035] Figure 5 This is provided by the embodiments of the present invention. Figure 3 A magnified view of a portion of the S-region. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0037] Example 1

[0038] This embodiment provides a pin-riveted anti-loosening bolt assembly, which achieves a triple anti-loosening mechanism of mechanical locking, structural limiting, and plastic deformation locking. (Refer to...) Figure 1 , Figure 3 and Figure 4 , Figure 1 This is a structural block diagram of the component. Figure 3 This is a sectional view of the assembly. Figure 4 This is an exploded view. The component mainly includes the bolt body 1, the lock nut 5, and the locking washer 103.

[0039] like Figure 3As shown, the bolt body 1 is the core load-bearing component of the connection. In one specific embodiment, both the bolt body 1 and its associated lock nut 5 are made of 42CrMo alloy steel and have undergone quenching and tempering heat treatment. The hardness of the bolt body 1 is controlled between HRC39 and 44 to ensure sufficient strength and toughness.

[0040] The head end face of the bolt body 1 is provided with a press-fit positioning hole. This press-fit positioning hole is a cylindrical blind hole, the axis of which is strictly coincident with the central axis of the bolt body 1. In one implementation, for bolts of M20 to M36 specifications, the diameter of the press-fit positioning hole can be designed to be 8mm to 12mm, and the depth to be 5mm to 8mm. The function of this structure is to ensure that during assembly, it can precisely cooperate with the positioning pin on the external press-fitting fixture, and through mechanical guidance, ensure that when the bolt body 1 is pressed into the mounting hole of the workpiece 2 or 3, the coaxiality error between its axis and the axis of the mounting hole is less than or equal to 0.1mm. This high-precision positioning avoids stress concentration caused by assembly misalignment, which is key to improving the fatigue life of the connection. To further optimize stress distribution, a transition fillet of R2-R3 is designed at the transition between the bolt head and the shank.

[0041] Along its axial direction, from the end furthest from the head towards the head, the shank of the bolt body 1 is provided with a fine thread section, a trapezoidal tooth section 4, and an end positioning groove in sequence. Compared with coarse threads, the fine thread section can provide more engagement turns and a larger contact area within the same thread length, thereby improving the self-locking performance and load-bearing capacity of the connection.

[0042] Trapezoidal toothed segment 4 is the core structure for achieving mechanical locking. The axial length of this segment can be 10mm to 15mm. Its tooth profile is an asymmetrical trapezoid. Specifically, refer to... Figure 5 The angle between its bearing tooth surface and the normal plane perpendicular to the bolt body axis Designed to be relatively small, ranging from 5° to 10°; while the angle between the non-load-bearing tooth surface and the normal plane. The angle is relatively large, ranging from 40° to 50°. This asymmetric design causes stress to be highly concentrated on the gently sloping load-bearing tooth surface when axial pressure is subsequently applied, thereby inducing controlled, directional micro-plastic deformation on this surface, rather than random or destructive deformation. In a specific geometric design, the trapezoidal tooth has a top width of 1 mm, a root width of 2 mm, and a tooth height of 1.5 mm.

[0043] The end positioning groove is located at the end of the rod and is used to mate with the positioning boss of the anti-loosening nut 5. This groove can be a circumferential groove surrounding the rod. In one embodiment, the groove has a rectangular cross-section with a width of 2 mm and a depth of 1 mm.

[0044] The anti-loosening nut 5 is a key component that works with the bolt body 1 to achieve locking. It is also made of 42CrMo alloy steel, but its hardness after heat treatment is controlled at HRC33-38, slightly lower than the hardness of the bolt body 1. This hardness gradient design ensures that during plastic deformation, the deformation mainly occurs on the lower-hardness nut teeth, thus protecting the integrity of the bolt body teeth, which are the main load-bearing component, and preventing them from cracking.

[0045] The outer contour of the lock nut 5 is designed with a dodecagonal structure. This structure requires a special dodecagonal socket tool for tightening. Compared to traditional hexagonal nuts, the dodecagonal structure provides more contact surface and a smaller turning angle, allowing the applied torque to be more evenly distributed on the outer wall of the nut. Torque fluctuation can be controlled within ±5%, thereby achieving more precise and stable preload control.

[0046] The inner hole structure of the anti-loosening nut 5 corresponds to the shank structure of the bolt body 1. It has an internal thread matching the fine-pitch thread section and an internal anti-loosening tooth pattern matching the trapezoidal tooth pattern section 4. The tooth profile and surface roughness of the internal anti-loosening tooth pattern are highly matched to the trapezoidal tooth pattern section 4 to ensure tight engagement.

[0047] On the end face of the lock nut 5 facing the bolt head, there is a ring-shaped locating boss. The size of this locating boss is precisely matched with the end locating groove on the bolt body 1, forming an interference fit. Specifically, the outer diameter of the locating boss in the free state is... Designed to be slightly larger than the inner diameter of the end locating groove in its free state. In a preferred configuration, the interference formed by the two is... The range is from 0.02mm to 0.05mm. When the nut is tightened into place, the positioning boss is pressed into the end positioning groove, and the radial interference force firmly restricts the radial and circumferential relative displacement between the nut and the bolt. This is the structural limit in the triple anti-loosening mechanism.

[0048] Locking washer 103, as an auxiliary anti-loosening element, is typically placed between the anti-loosening nut 5 and the workpiece 3. This washer is made of highly elastic materials such as 65Mn spring steel, with a hardness reaching HRC40-45. Its inner hole also has anti-loosening teeth that match the trapezoidal toothed section 4. After assembly, it not only provides a certain axial elastic preload, but its internal teeth also mesh with the trapezoidal teeth of the bolt, further increasing the anti-loosening frictional torque.

[0049] The working principle of the anti-loosening bolt assembly in this embodiment is as follows: A basic axial preload is provided by tightening the fine-pitch thread; the trapezoidal toothed section 4 meshes with the internal anti-loosening teeth of the anti-loosening nut 5, forming a mechanical tooth lock, fundamentally preventing relative rotation caused by vibration; the interference fit between the positioning boss and the end positioning groove provides radial and circumferential structural limits, preventing any slight displacement of the nut; through subsequent application of axial pressure, the meshing teeth undergo slight plastic deformation, completely eliminating manufacturing tolerances and fit clearances, forming a permanent, irreversible plastic deformation lock. The combination of these three mechanisms enables the assembly to achieve high connection reliability under high vibration and high load conditions.

[0050] Example 2

[0051] This embodiment provides an assembly method for use with the anti-loosening bolt assembly described in Embodiment 1. (Refer to...) Figure 2 This method upgrades the traditional elastic pre-tightening assembly process to a precision pin riveting process that incorporates plastic deformation locking. The method mainly includes the following steps:

[0052] Bolt installation steps

[0053] Before assembly begins, the workpiece must be pre-treated. For example, when machining mounting holes on wind turbine tower flanges or automobile beams, the diameter of the hole should be 0.05mm to 0.1mm larger than the diameter of the smooth section of the bolt body to ensure smooth insertion. At the same time, the hole wall needs to be cleaned to remove burrs and oil stains.

[0054] Subsequently, the bolt body 1 is passed through the mounting holes of workpieces 2 and 3. At this point, using a specialized press-fitting fixture, the locating pin is precisely inserted into the press-fitting locating hole on the bolt head. Guided by the locating pin, axial pressure is applied to the bolt body 1, pressing it coaxially into and fixing it within the workpiece. In this step, the precise fit between the locating pin and the locating hole ensures that the coaxiality error between the central axis of the bolt body and the central axis of the mounting hole is less than or equal to 0.1 mm, laying the foundation for subsequent uniform load-bearing.

[0055] Nut tightening steps

[0056] After the bolt body 1 is fixed, the locking washer is fitted onto the bolt shank, causing its internal teeth to initially engage with the trapezoidal toothed section 4. Next, the lock nut 5, with a dodecagonal outer contour, is screwed into the fine-threaded section of the bolt. A special dodecagonal socket tool is used to apply a pre-tightening torque to the lock nut 5; the torque value is set according to the specific application, for example, it can be controlled between 300 N·m and 500 N·m. Tightening continues until the locating boss of the lock nut 5 aligns with the end locating groove of the bolt body 1 and is embedded therein due to the interference fit. At this point, the internal lock teeth of the nut are also fully engaged with the trapezoidal toothed section 4 of the bolt.

[0057] Pin-riveting fixing steps

[0058] This is the key step that distinguishes this method from traditional bolt assembly. After the nut is tightened to a preset torque, a preset pure axial pressure is applied to the end face of the lock nut 5 using a press-fitting tool. The magnitude of this axial pressure is precisely calculated. Specifically, the preset axial pressure... It is based on the material yield strength of the trapezoidal toothed segment. Effective bearing area of ​​tooth meshing This is determined by [the specific method used]. To ensure the meshing surface stably enters the plastic deformation region, while avoiding macroscopic fracture or excessive damage to the material due to excessive pressure, this axial pressure [is crucial]. They typically satisfy the following mathematical relationship:

[0059]

[0060] in, Indicates the applied axial pressure; Indicates the yield strength of the bolt or nut material; This indicates the effective load-bearing area of ​​the trapezoidal toothed pattern engaging with the internal anti-loosening toothed pattern. In practical applications, such as for M24 specification components, this axial pressure can be set in the range of 5kN to 10kN.

[0061] Under this axial pressure, due to the asymmetrical tooth design, stress is concentrated on the bearing tooth surface, causing microscopic plastic deformation at the contact surface between the internal anti-loosening teeth of the nut and the trapezoidal tooth segments of the bolt. This plastic deformation manifests as the formation of micro-indentations of controllable depth on the bearing tooth surface. This process causes dislocations and slippage in the lattice of the tooth surface, resulting in a work hardening effect, further improving the hardness and wear resistance of the contact surface. The depth of plastic deformation... Precisely controlled within the range of 0.01mm to 0.03mm, this depth is sufficient to completely eliminate the minute gaps between the tooth surfaces caused by manufacturing tolerances and elastic deformation, forming an irreversible mechanical locking state. At the same time, because the deformation is small and controllable, excessive stress concentration at the tooth root is avoided, thus ensuring the long-term fatigue resistance of the connection structure under high-frequency alternating loads.

[0062] Alternatively, to provide additional safety redundancy in certain extreme environments, after the pin-riveting process is completed, laser spot welding can be used for local reinforcement at the mating point between the bolt end positioning groove and the nut positioning boss. For example, two to three weld points with a diameter of 2 mm can be evenly distributed circumferentially.

[0063] Application examples and effects

[0064] Taking the application of high-speed railway bridge bearing connections as an example, the M30×2 pin-riveting anti-loosening bolt assembly of this application was selected. During assembly, the applied nut preload torque was 600 N·m, and the subsequent applied pin-riveting axial pressure was 8 kN. After 12 months of actual operation, the connection underwent more than 5,000 hours of cumulative vibration from train operation. The test results showed no signs of loosening at the connection, and stress sensor monitoring revealed that the local stress in its key areas was reduced by 25% compared to connections using traditional high-strength bolts.

[0065] The table below shows a performance comparison between the anti-loosening bolts of this application and traditional M24 high-strength bolts under the same test conditions:

[0066] Performance indicators Traditional bolts This application relates to anti-loosening bolts. Connection loosening rate 42% 0% Shear strength 110MPa 220MPa Assembly coaxiality error 0.8mm 0.08mm Fatigue life (number of cycles) Second-rate Second-rate

[0067] As can be seen from the table, the technical solution provided in this application shows significant advantages in terms of anti-loosening reliability, connection strength, assembly accuracy, and fatigue resistance.

[0068] It should be noted that the pin-riveting anti-loosening bolt assembly and method of this application are not limited to the above-mentioned application scenarios, but can also be widely used in any connection field that requires high strength, high reliability, and long-term maintenance-free operation, such as commercial vehicle beam connection, new energy vehicle battery pack frame, subway vehicle bogie, excavator boom / stick connection, crane boom segment connection, and offshore platform steel structure.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A pin-riveted anti-loosening bolt assembly, characterized in that, Includes bolt body 1, anti-loosening nut 5, and locking washer 103; The bolt body 1 has a fine thread section, a trapezoidal tooth section 4 and an end positioning groove in sequence along its axial direction. The anti-loosening nut 5 has an internal thread that mates with the fine thread section. The inner hole of the anti-loosening nut 5 is also provided with an internal anti-loosening tooth pattern that meshes with the trapezoidal tooth pattern section 4. Furthermore, a positioning boss that mates with the end positioning groove is provided on the end face facing the head side of the bolt body 1. When the anti-loosening nut 5 is assembled with the bolt body 1, the positioning boss and the end positioning groove form an interference fit, and the internal anti-loosening teeth and the trapezoidal tooth segment 4 undergo plastic deformation under axial pressure to form a permanent locking structure.

2. The anti-loosening bolt assembly according to claim 1, characterized in that, The head end face of the bolt body 1 is provided with a press-fit positioning hole. The press-fit positioning hole is a cylindrical blind hole with its axis coinciding with the central axis of the bolt body. It is used to cooperate with the positioning pin of the external tooling during assembly to ensure that the coaxiality error of the assembly is less than or equal to 0.1mm.

3. The anti-loosening bolt assembly according to claim 1, characterized in that, The positioning boss is an annular boss circumferentially arranged around the inner hole of the anti-loosening nut 5, and the end positioning groove is a circumferential groove circumferentially arranged around the shank of the bolt body 1; the outer diameter of the positioning boss in the free state is... Larger than the inner diameter of the end positioning groove in its free state The two form an over-compensation pair, and the amount of over-compensation... The range is configured to be from 0.02mm to 0.05mm.

4. The anti-loosening bolt assembly according to claim 1, characterized in that, The trapezoidal toothed segment 4 has an asymmetrical trapezoidal tooth shape, and the angle between its bearing tooth surface and the normal plane perpendicular to the axis of the bolt body is... Smaller than the angle between its non-load-bearing tooth surface and the normal plane. The included angle The range is 5° to 10°, the included angle The range is 40° to 50°; the tooth shape of the internal anti-loosening tooth pattern matches the tooth shape of the trapezoidal tooth pattern segment. This asymmetrical structure causes stress to concentrate on the bearing tooth surface when axial pressure is applied, and induces it to undergo directional and controllable plastic deformation.

5. The anti-loosening bolt assembly according to claim 1, characterized in that, The outer contour of the lock nut is a dodecagonal structure, which is used to cooperate with a dodecagonal socket tool to apply a precise and stable preload torque.

6. A method for assembling a pin-fitted anti-loosening bolt, the pin-fitted anti-loosening bolt comprising a bolt body and an anti-loosening nut, wherein the shank of the bolt body is provided with a trapezoidal toothed section and an end positioning groove, and its head is provided with a press-fit positioning hole, and the anti-loosening nut is provided with internal anti-loosening teeth that engage with the trapezoidal toothed section and a positioning boss that cooperates with the end positioning groove; characterized in that, Includes the following steps: The bolt installation steps involve inserting the positioning pin of the press-fitting fixture into the press-fitting positioning hole and pressing the bolt body coaxially into the workpiece. In the nut tightening step, the anti-loosening nut is screwed into the bolt body until the positioning boss and the end positioning groove are engaged, and the internal anti-loosening teeth are fully engaged with the trapezoidal tooth segment; In the pin-riveting fixing step, a preset axial pressure is applied to the tightened anti-loosening nut, causing plastic deformation of the meshing surface between the internal anti-loosening teeth and the trapezoidal tooth segment.

7. The assembly method according to claim 6, characterized in that, In the bolt installation step, by precisely matching the locating pin with the press-fit locating hole, the bolt body is pressed into the preset mounting hole of the workpiece, and the coaxiality error between the central axis of the bolt body and the central axis of the preset mounting hole is less than or equal to 0.1 mm.

8. The assembly method according to claim 6, characterized in that, In the pin-fitting step, the preset axial pressure The size is based on the material yield strength of the trapezoidal toothed segment. Effective bearing area of ​​tooth meshing The predetermined axial pressure Satisfying mathematical relations This ensures that the meshing surface stably enters the plastic deformation region, while avoiding macroscopic fracture of the material due to excessive pressure.

9. The assembly method according to claim 8, characterized in that, The plastic deformation is a micro-indentation of controllable depth formed on the bearing tooth surface of the internal anti-loosening teeth and the trapezoidal tooth segment. This plastic deformation causes dislocations and slippage in the surface lattice of the bearing tooth surface, resulting in a work hardening effect; the depth of the plastic deformation... Precisely controlled within the range of 0.01mm to 0.03mm, this depth is sufficient to completely eliminate manufacturing tolerances and fit clearances between tooth surfaces to form an irreversible mechanical lock-in, and this depth is configured to avoid excessive stress concentration at the tooth root.

10. The assembly method according to claim 6, characterized in that, In the nut tightening step, a special dodecagonal socket tool is used to apply a preload torque to the lock nut, which has a dodecagonal outer contour.

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