Wear self-checking structure of copper-steel composite nut and nut

Abstract

The invention discloses an abrasion self-checking structure of a copper-steel composite nut and the nut. The abrasion self-checking structure of the copper-steel composite nut comprises a nut body and a plurality of passive monitoring parts, and / or comprises the nut body and a plurality of active monitoring parts; the multiple passive monitoring pieces and the multiple active monitoring pieces are symmetrically arranged on the side face of the nut body. The nut body is a steel-based nut, a through hole is formed in the nut body, a copper lubricating coating is attached to the inner surface of the through hole in a metallurgical bonding mode, and internal threads are arranged on the copper lubricating coating. The passive monitoring piece and the active monitoring piece are used for providing early warning prompt when the nut body is abraded to a preset abrasion threshold value in the process that the bolt is inserted into the through hole and is in threaded connection with the nut body. Dual wear monitoring combining a passive monitoring part and an active monitoring part is adopted, the passive monitoring part forms colored traces through wear exposure of a low-hardness material, and visual warning is provided; the active monitoring member triggers an alarm signal through the electric detection element conductive loop.

Description

Technical Field

[0001] The present invention relates to the technical field of metal composite material processing and mechanical structure design, and in particular to a wear self-detection structure of a copper-steel composite nut and the nut. Background Art

[0002] At present, despite the various forms and processing methods of nuts, the following prominent problems still exist in their actual applications: First, the wear monitoring capability is weak. Existing products mostly rely on regular manual inspections and cannot achieve real-time early warning of the wear threshold. When the alloy copper layer is worn out, the steel base and the screw steel base directly collide and rub against each other, which can easily cause serious wear losses. Second, the function is single. Traditional nuts are only used as mechanical connection components. They lack active detection and early warning functions, making it difficult to monitor the wear status in real time and unable to meet the needs of fastener safety monitoring under high load and high wear conditions. Third, the copper-steel bonding strength is insufficient. In existing products, the copper layer and the steel nut are mostly connected with a smooth surface, and the bonding force is weak, which directly affects the service life and reliability of the nut. Summary of the Invention

[0003] The embodiment of the present invention provides a wear self-detection structure and nut of a copper-steel composite nut to solve the technical problem in the prior art that traditional fasteners lack online status monitoring and preventive maintenance prompts under high load and high wear conditions, and cannot dynamically grasp their wear conditions.

[0004] In view of the above technical problems, an embodiment of the present invention provides a wear self-detection structure for a copper-steel composite nut, comprising a nut body and a plurality of passive monitoring components, and / or a nut body and a plurality of active monitoring components; the plurality of passive monitoring components and the plurality of active monitoring components are symmetrically arranged on the side of the nut body; the nut body is a steel-based nut and is formed with a through hole, the inner surface of the through hole is bonded with a copper lubricating coating by metallurgical bonding, and the copper lubricating coating is provided with an internal thread;

[0005] The passive monitoring component and the active monitoring component are used to provide an early warning when the nut body is worn to a preset wear threshold during the process of the bolt being inserted into the through hole and being threadedly connected to the nut body.

[0006] Optionally, the hardness of the passive monitoring component is less than the hardness of the nut body; the multiple passive monitoring components are symmetrically arranged along the circumferential side of the nut body, and the end face of the passive monitoring component facing the internal thread is provided with an engaging surface, and the engaging surface is consistent with the internal thread.

[0007] Optionally, a rough surface is provided on the outer surface of the occlusal curved surface, and the rough surface is a microwave convex surface.

[0008] Optionally, a preset hole is provided on the side of the nut body, and the passive monitoring component is a graphite column, which is interference-fitted with the preset hole.

[0009] Optionally, the graphite column includes a plurality of graphite segments connected in sequence, and a preset buffer gap is set between adjacent graphite segments.

[0010] Optionally, it also includes a group of through holes symmetrically arranged on the side of the nut body, and the active monitoring component includes a first electrode assembly embedded in the through holes, a second electrode assembly, a conductive component built into the first electrode assembly and the second electrode assembly, and an external circuit electrically connected to the conductive component.

[0011] Optionally, the first electrode assembly and the second electrode assembly have the same structure, both comprising an electrode steel body, a copper coupling layer provided on an end surface of the electrode steel body facing the internal thread, and an insulating layer;

[0012] The insulating layer includes a first insulating layer arranged between the steel body of the electrode component and the copper coupling layer, and a second insulating layer covered on the outer surface of the steel body of the electrode component.

[0013] Optionally, the copper coupling layer matches the internal thread profile; the first insulating layer and the second insulating layer are non-metallic insulating layers.

[0014] Optionally, the copper lubricating coating has a thickness of 0.01 mm to 300 mm.

[0015] The present invention also provides a nut, comprising the wear self-detection structure of the copper-steel composite nut.

[0016] In the present invention, the wear self-inspection structure of the copper-steel composite nut includes a nut body and multiple passive monitoring parts, and / or includes a nut body and multiple active monitoring parts; multiple passive monitoring parts and multiple active monitoring parts are symmetrically arranged on the side of the nut body; the nut body is a steel-based nut and is formed with a through hole, and the inner surface of the through hole is adhered with a copper lubricating coating through metallurgical bonding, and the copper lubricating coating is provided with an internal thread; the passive monitoring part and the active monitoring part are used to provide an early warning prompt when the nut body is worn to a preset wear threshold during the process of the bolt being inserted into the through hole and threadedly connected to the nut body.

[0017] In the present invention, due to the use of a wear self-detection structure that combines passive monitoring parts and active monitoring parts, a dual monitoring and protection mechanism is formed, which achieves the dual technical goals of online status monitoring of fasteners and preventive wear maintenance prompts. The passive monitoring part is made of low-hardness material. When the nut body is worn to a preset wear threshold, the passive monitoring part is exposed and forms a colored mark on the surface of the bolt, realizing a visual warning. The active monitoring part uses an electrical detection element. When the nut body is worn to a threshold, the conductive part of the electrical detection element contacts the bolt to form a conductive circuit, triggering an alarm signal to remind maintenance. In addition, the surface of the internal thread of the through hole of the nut body is bonded with a copper lubricating coating through metallurgical bonding. Copper and steel are bonded by embedding and metallurgical mixing. Microscopically, the bonding area is larger and the bonding strength is higher, which effectively improves the wear resistance and service life of the nut body. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0019] Figure 1 Schematic diagram of a wear self-detection structure of a copper-steel composite nut according to an embodiment of the present invention;

[0020] Figure 2 yes Figure 1 A cross-sectional view of the wear self-detection structure;

[0021] Figure 3 yes Figure 2 Schematic diagram of the enlarged structure of part A;

[0022] Figure 4 Schematic diagram of a wear self-detection structure of a copper-steel composite nut in another embodiment of the present invention;

[0023] Figure 5 yes Figure 4 A cross-sectional view of the wear self-detection structure;

[0024] Figure 6 1 is a circuit diagram of a wear self-detection structure of a copper-steel composite nut according to an embodiment of the present invention.

[0025] The reference numerals in the specification are as follows:

[0026] 1- nut body, 11- through hole, 12- internal thread, 2- passive monitoring part, 21- occlusal surface, 3- active monitoring part, 31- first electrode assembly, 311- electrode part steel body, 312- copper coupling layer, 313- insulating layer, 32- second electrode assembly, 4- copper lubricating coating, 5- bolt, 6- pre-set hole, 7- through hole, 8- conductive part. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0029] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0030] like Figures 1 to 6As shown, an embodiment of the present invention provides a wear self-detection structure for a copper-steel composite nut, comprising a nut body 1 and a plurality of passive monitoring components 2, and / or comprising a nut body 1 and a plurality of active monitoring components 3; the plurality of passive monitoring components 2 and the plurality of active monitoring components 3 are symmetrically arranged on the side surface (i.e., the non-bearing surface) of the nut body 1; the nut body 1 is a steel-based nut, and is formed with a through hole 11, and the inner surface of the through hole 11 is adhered with a copper lubricating coating 4 by metallurgical bonding, and the copper lubricating coating 4 is provided with an internal thread 12; the passive monitoring component 2 and the active monitoring component 3 are used for providing an early warning prompt when the nut body 1 is worn to a preset wear threshold during the process of the bolt 5 being inserted into the through hole 11 and being threadedly connected to the nut body 1. Among them, the base of the nut body 1 is made of steel, preferably medium carbon steel or alloy steel, and the steel internal thread 12 is fitted with a copper lubricating coating 4 (the copper layer is on the internal thread 12, that is, the teeth of the internal thread 12 are copper-clad steel structures). The two are combined by embedding and metallurgical mixing. The microscopic bonding area is larger and the bonding strength is higher; the thickness of the copper lubricating coating 4 is selected according to the specifications of the nut body 1. By heating to the recrystallization temperature of copper and applying pressure, the copper atoms and the steel matrix form a metal bond, and the bonding strength can reach more than 200MPa. It is understandable that the passive monitoring part 2 and the active monitoring part 3 can be set at the same time, or can be set independently. The passive monitoring part 2 can adopt a passive monitoring part 2 with lower hardness. When the nut body 1 is worn to a preset wear threshold, the passive monitoring part 2 is worn and exposed, thereby forming an obvious colored mark on the surface of the bolt 5. The active monitoring component 3 can adopt an electrical detection element. When the nut body 1 is worn to a preset wear threshold, the conductive part in the electrical detection element contacts the bolt 5 to form a conductive circuit, triggering an alarm signal of the external circuit to promptly remind the user to perform maintenance.

[0031] In the present invention, due to the use of a wear self-detection structure that combines a passive monitoring component 2 and an active monitoring component 3, a dual monitoring and protection mechanism is formed, achieving the dual technical goals of online status monitoring of fasteners and preventive wear maintenance prompts. The passive monitoring component 2 is made of low-hardness material. When the nut body 1 is worn to a preset wear threshold, the passive monitoring component 2 is exposed due to wear and forms a colored mark on the surface of the bolt 5, realizing a visual warning. The active monitoring component 3 uses an electrical detection element. When the nut body 1 is worn to a threshold, the conductive part of the electrical detection element contacts the bolt 5 to form a conductive circuit, triggering an alarm signal to remind maintenance. In addition, the surface of the internal thread 12 of the through hole 11 of the nut body 1 is bonded with a copper lubricating coating 4 by metallurgical bonding. Copper and steel are bonded by embedding and metallurgical mixing. Microscopically, the bonding area is larger and the bonding strength is higher, which effectively improves the wear resistance and service life of the nut body 1.

[0032] In one embodiment, if Figures 1 to 3As shown, the passive monitoring element 2 has a lower hardness than the nut body 1. The multiple passive monitoring elements 2 are symmetrically arranged along the circumferential side of the nut body 1. The end faces of the passive monitoring elements 2 facing the internal thread 12 are provided with an engaging curved surface 21 that aligns with the internal thread 12. As can be understood, the shape of the engaging curved surface 21 is consistent with the internal thread 12, enabling the passive monitoring element 2 to form good contact and directional load distribution with the surface of the bolt 5 during the engagement between the nut and the bolt 5. Due to the lower hardness of the passive monitoring element 2, when the nut body 1 wears to a preset threshold, the passive monitoring element 2 will wear and become exposed first. The detached material forms a noticeable colored mark on the surface of the bolt 5, thus providing a visual warning function. This structure not only ensures the reliability of the nut body 1 in wear monitoring, but also, through the design of the engaging curved surface 21 that aligns with the internal thread 12, ensures the overall mechanical performance and connection stability of the nut body 1, preventing the passive monitoring element 2 from affecting the normal function of the nut body 1. Multiple passive monitoring components 2 are arranged symmetrically along the side surface (non-bearing surface) of the nut body 1 to form a multi-dimensional wear monitoring network. This symmetrical design ensures that each monitoring point is evenly stressed, avoiding misjudgment or omission caused by wear deviation in a single direction; the early warning signal triggered by multiple points can comprehensively evaluate the actual wear status of the nut body 1 and improve the reliability of the monitoring results.

[0033] In one embodiment, if Figures 2 to 3 As shown, the outer surface of the engaging curved surface 21 is provided with a rough surface, and the rough surface is a microwave raised surface. It can be understood that the setting of the microwave raised surface significantly increases the actual contact area between the passive monitoring component 2 and the bolt 5 by increasing the microscopic roughness of the surface, thereby enhancing the friction and the bite effect between the two. Due to the presence of the rough surface (microwave raised surface), the lubricating column (passive monitoring component 2) is more likely to form a contact load distribution with the surface of the bolt 5 during the connection process between the nut body 1 and the bolt 5, making the passive monitoring component 2 more susceptible to wear during the wear process of the nut body 1. In this way, the rough surface design has dual functions: on the one hand, it improves the lubrication effect by increasing the contact area, and on the other hand, it realizes low-cost status monitoring through color marking.

[0034] In one embodiment, if Figures 1 to 3As shown, the wear self-detection structure of the copper-steel composite nut also includes a preset hole 6 opened on the side of the nut body 1. The passive monitoring component 2 is a graphite column, which is interference-fitted with the preset hole 6. It can be understood that a porous honeycomb-shaped high-purity graphite column (purity ≥99%, density 1.7-1.9g / cm3) is arranged in a circumferential array on the non-bearing surface of the nut body 1 and is pressed into the preset hole 6 with an interference fit, forming a lubrication-monitoring composite unit that penetrates the nut body 1. The inner end of the graphite column is machined into a curved surface that fully matches the tooth profile, pitch, and rotation direction of the internal thread 12, ensuring a directional contact load distribution when it engages with the bolt 5. Not only does it retain the lubricity of the copper lubricating coating 4, but it also realizes a passive early warning function by exposing the wear marks of the graphite column. When the nut body 1 wears to a critical threshold, the particles shed from the graphite column due to wear will form a continuous black track on the surface of the bolt 5. This visual monitoring method can intuitively remind maintenance personnel of the wear status of the nut, allowing for timely replacement or maintenance.

[0035] Furthermore, the graphite columns' self-lubricating properties are achieved through their interlayer slip mechanism, reducing the coefficient of kinetic friction to below 0.1. This significantly reduces friction between the nut body 1 and the bolt 5, thereby reducing wear and extending the nut's service life. This design upgrades the traditional consumable lubrication component into a composite functional unit that combines friction pair protection with intelligent early warning. This not only improves the reliability of the nut body 1, but also enhances its applicability under high-load, high-wear conditions.

[0036] Furthermore, the design value of the interference fit of the graphite column pressed into the preset hole 6 can be calculated according to the different specifications of the nut body 1. Taking the M12*1.75 nut as an example, the following formula is used to calculate whether the fitting stress of the lubricating column meets the requirements.

[0037]

[0038] Among them, E is the elastic modulus of graphite, δ is the interference, and ν is the Poisson's ratio of graphite.

[0039] First, calculate the pitch diameter of the thread:

[0040] d2=12-1.75*0.6495=10.863mm.

[0041] Then, perform interference fit stress check:

[0042]

[0043] Among them, E is taken as 12GPa and δ is taken as 0.03mm. The matching stress is less than the graphite compressive strength of 50MPa, which meets the safety requirements.

[0044] In one embodiment, the graphite column includes a plurality of graphite segments (not shown) connected in sequence, and a preset buffer gap is set between adjacent graphite segments. It is understandable that if the graphite column is a continuous whole, then under high temperature or high stress environment, the graphite column may have problems such as peeling and cracking due to mismatch of thermal expansion coefficient or stress concentration. In order to avoid this phenomenon, the graphite column is designed into segments, which can effectively reduce the stress concentration problem caused by the difference in thermal expansion coefficient. The segmented design allows each graphite segment to adapt to thermal expansion independently, thereby reducing the thermal stress risk of the overall structure. In the continuous graphite column design, due to the difference in thermal expansion coefficient, the graphite column may generate large thermal stress in a high temperature environment. This stress may cause the bond between the graphite column and the copper layer or steel matrix to fail, and may even cause the graphite column to peel off; by setting a preset buffer gap, the graphite segment is allowed to have a buffer space during thermal expansion, thereby avoiding failure caused by thermal stress.

[0045] In one embodiment, if Figures 4 to 6 As shown, the wear self-detection structure of the copper-steel composite nut also includes a group of through holes 7 symmetrically arranged on the side of the nut body 1, and the active monitoring component 3 includes a first electrode assembly 31 and a second electrode assembly 32 embedded in the through hole 7, a conductive member 8 built into the first electrode assembly 31 and the second electrode assembly 32, and an external circuit electrically connected to the conductive member 8. It can be understood that the position and form of the through hole 11 are not limited, and it is sufficient to ensure that the external circuit is not conductive when the nut body 1 is not worn and is conductive after wear. By providing symmetrical through holes 7 on the side of the nut body 1 and embedding the first electrode assembly 31 and the second electrode assembly 32, an active wear alarm is realized, breaking through the functional limitation of traditional nuts that are only mechanically connected. Specifically, as Figure 6 As shown, when the copper lubricating coating 4 is completely worn, the steel substrates of the first and second electrode assemblies 31 and 32 come into contact with the bolt 5, forming a conductive loop. This triggers a warning signal in an external circuit, alerting the user that the nut requires maintenance. This active monitoring method not only monitors the wear status of the nut in real time but also issues an alert before wear reaches a dangerous level.

[0046] In one embodiment, if Figures 1 to 2As shown, the first electrode assembly 31 and the second electrode assembly 32 have the same structure, both including an electrode steel body 311, a copper coupling layer 312 disposed on the end face of the electrode steel body 311 facing the internal thread 12, and an insulating layer 313; the insulating layer 313 includes a first insulating layer 313 disposed between the electrode steel body 311 and the copper coupling layer 312, and a second insulating layer 313 coated on the outer surface of the electrode steel body 311. It is understandable that the insulating layer 313 is generally made of a non-metallic material, such as PE, PVC, polytetrafluoroethylene, ceramic, silicon nitride, etc. The copper layer of the first electrode assembly 31 and the second electrode assembly 32 is formed simultaneously with the insulating layer 313. When the nut body 1 is not worn, the insulating layer 313 can ensure that the first electrode assembly 31 and the second electrode assembly 32 remain insulated from the nut body 1, preventing false alarms. When the nut body 1 is worn to a preset threshold, its copper layer is worn through, and its steel base contacts the bolt 5, forming a conductive circuit, triggering an external warning device to alert maintenance personnel; this structure not only breaks through the limitation of traditional nuts as only mechanical connectors, but also effectively improves the safety and reliability of the nut body 1 under high-load and high-wear conditions by real-time monitoring of the wear status and early warning.

[0047] In one embodiment, if Figure 5 As shown, the copper coupling layer 312 matches the profile of the internal thread 12; the first and second insulating layers 313 are non-metallic insulating layers 313. As can be understood, the surface of the copper coupling layer 312 is configured with a curved surface that matches the profile of the internal thread 12, ensuring a directional contact load distribution when engaged with the bolt 5, thus forming a good mechanical and electrical connection between the copper coupling layer 312 and the bolt 5. This structure not only ensures the electrical insulation performance of the nut body 1 under normal operating conditions, but also improves the mechanical properties and wear resistance of the nut body 1 through the close fit between the copper coupling layer 312 and the internal thread 12.

[0048] In one embodiment, if Figure 5 As shown, the thickness of the copper lubricating coating 4 is 0.01mm-300mm. It is understandable that the thickness of the copper lubricating coating 4 can be set according to demand, specifically, according to the specifications of the nut, the operating conditions, the expected wear life, the lubrication performance control requirements, the heat conduction optimization, the mechanical strength balance and other factors. The thickness of the copper lubricating coating 4 will also affect the thermal conductivity and mechanical strength of the nut. The appropriate thickness can optimize the overall performance of the nut while ensuring the lubrication and monitoring functions, so that it can maintain a good working condition under various complex working conditions. In addition, the copper lubricating coating 4 can absorb vibration energy through plastic deformation to form a gradient wear zone, thereby extending the exposure time of the steel substrate.

[0049] The present invention also provides a nut, including the wear self-detection structure of the copper-steel composite nut mentioned above. In the wear self-detection structure of the copper-steel composite nut in the above embodiment of the present invention, the wear self-detection structure of the copper-steel composite nut includes a nut body 1 and a plurality of passive monitoring parts 2, and / or includes a nut body 1 and a plurality of active monitoring parts 3; the plurality of passive monitoring parts 2 and the plurality of active monitoring parts 3 are symmetrically arranged on the side of the nut body 1; the nut body 1 is a steel-based nut, and is formed with a through hole 11, and the inner surface of the through hole 11 is bonded with a copper lubricating coating 4 by metallurgical bonding, and the copper lubricating coating 4 is provided with an internal thread 12; the passive monitoring part 2 and the active monitoring part 3 are used to provide an early warning prompt when the nut body 1 is worn to a preset wear threshold during the process of the bolt 5 being inserted into the through hole 11 and being threadedly connected to the nut body 1.

[0050] The nuts in the above embodiments of the present invention are compatible with both passive visual warnings and active circuit alarms. Users can choose a suitable monitoring method according to actual working conditions. Whether it is a scenario that requires quick and intuitive judgment of the nut wear status or a scenario that requires real-time and automatic monitoring, it can meet the needs.

[0051] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A wear self-detection structure for a copper-steel composite nut, characterized in that: The invention comprises a nut body (1) and a plurality of passive monitoring components (2), and / or a nut body (1) and a plurality of active monitoring components (3); the plurality of passive monitoring components (2) and the plurality of active monitoring components (3) are symmetrically arranged on the side of the nut body (1); the nut body (1) is a steel-based nut and is formed with a through hole (11); the inner surface of the through hole (11) is bonded with a copper lubricating coating (4) by metallurgical bonding, and the copper lubricating coating (4) is provided with an internal thread (12); The passive monitoring component (2) and the active monitoring component (3) are used to provide an early warning when the nut body (1) is worn to a preset wear threshold value during the process of the bolt (5) being inserted into the through hole (11) and being threadedly connected to the nut body (1).

2. The wear self-detection structure of the copper-steel composite nut according to claim 1 is characterized in that: The hardness of the passive monitoring component (2) is less than the hardness of the nut body (1); the multiple passive monitoring components (2) are symmetrically arranged along the circumferential side of the nut body (1); the end face of the passive monitoring component (2) facing the internal thread (12) is provided with an engaging curved surface (21), and the engaging curved surface (21) is consistent with the internal thread (12).

3. The wear self-detection structure of the copper-steel composite nut according to claim 2 is characterized in that: The outer surface of the occlusal curved surface (21) is provided with a rough surface, and the rough surface is a microwave convex surface.

4. The wear self-detection structure of the copper-steel composite nut according to claim 3 is characterized in that: It also includes a preset hole (6) opened on the side of the nut body (1); the passive monitoring component (2) is a graphite column, and the graphite column is interference-fitted with the preset hole (6).

5. The wear self-detection structure of the copper-steel composite nut according to claim 4 is characterized in that: The graphite column includes a plurality of graphite segments connected in sequence, and a preset buffer gap is set between adjacent graphite segments.

6. The wear self-detection structure of the copper-steel composite nut according to claim 1 is characterized in that: The invention also includes a group of through holes (7) symmetrically arranged on the side of the nut body (1), and the active monitoring component (3) includes a first electrode component (31) embedded in the through hole (7), a second electrode component (32), a conductive component (8) built into the first electrode component (31) and the second electrode component (32), and an external circuit electrically connected to the conductive component (8).

7. The wear self-detection structure of the copper-steel composite nut according to claim 6 is characterized in that: The first electrode assembly (31) and the second electrode assembly (32) have the same structure, and both comprise an electrode steel body (311), a copper coupling layer (312) arranged on the end surface of the electrode steel body (311) facing the internal thread (12), and an insulating layer (313); The insulating layer (313) comprises a first insulating layer (313) disposed between the electrode steel body (311) and the copper coupling layer (312), and a second insulating layer (313) covering the outer surface of the electrode steel body (311).

8. The wear self-detection structure of the copper-steel composite nut according to claim 7, characterized in that: The copper coupling layer (312) matches the tooth shape of the internal thread (12); the first insulating layer (313) and the second insulating layer (313) are non-metallic insulating layers (313).

9. The wear self-detection structure of the copper-steel composite nut according to claim 1, characterized in that: The copper lubricating coating (4) has a thickness of 0.01 mm to 300 mm.

10. A nut, characterized in that: The invention comprises a wear self-detection structure of a copper-steel composite nut according to any one of claims 1 to 9.

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