A self-locking bolt and fastening device

Abstract

The application discloses a self-locking bolt and a fastening device, and belongs to the technical field of fasteners. The self-locking bolt comprises a nut provided with an internal thread and a screw rod provided with an external thread. The internal thread and the external thread comprise matching thread units. The thread units at the matching positions of the internal thread and the external thread are different. The thread units comprise a plurality of first thread units and a plurality of second thread units. Each second thread unit comprises a thread groove. The thread groove comprises a mortise structure with an axial height. The first thread unit comprises a thread structure. When the thread structure is screwed into a pre-tightening state along the thread groove, a bearing structure with a vertical axial pre-tightening force is formed between the mortise structure and the thread structure. A self-locking structure is formed between the mortise structure and the thread structure through a fitting surface in the screwing direction of the nut. A compensator is arranged between the nut and a workpiece to be fastened. When the nut and the compensator are screwed into a preset position, the compensator generates an axial displacement in a predetermined direction. The preset direction is a rotating direction away from the nut.

Description

Technical Field

[0001] This application relates to the field of fastener technology, and more specifically to a self-locking bolt and fastening device. Background Technology

[0002] Bolted connections are the most basic and crucial connection method in mechanical equipment, and their reliability directly affects the overall safety and stable operation of the equipment. Under dynamic operating conditions such as vibration, impact, and temperature fluctuations, traditional threaded connections are prone to loosening and failure due to preload decay.

[0003] Traditional threads consist of a continuous helix with a fixed slope. When the nut is tightened, the threaded contact surface forms a slope. When the connection point is subjected to axial impact, the impact force is decomposed into two components along this slope: a clamping force perpendicular to the slope, and a separating force parallel to the slope that drives the nut to rotate. The latter is the "wedge effect" that causes loosening.

[0004] Under prolonged high-load impact and vibration, the impulse of the instantaneous impact load will generate a large tangential component on the threaded contact surface. This component is sufficient to break the static balance maintained by the friction of the threaded surface, causing microscopic relative sliding on the threaded contact surface. Over time, this microscopic relative sliding will eventually lead to loosening of the bolt connection and affect normal use. Summary of the Invention

[0005] The purpose of this application is to provide a self-locking bolt and fastening device that can solve the problem in practical applications where the presence of an inclined plane causes slight slippage of the threaded contact surface, resulting in reverse rotation and axial displacement of the nut. Under the continuous action of the axial reaction force of the preload, the displacement accumulates in a specific direction, eventually leading to complete connection failure. The self-locking bolt significantly improves the threaded connection effect between the nut and the screw, greatly enhancing stability.

[0006] In a first aspect, embodiments of this application provide a self-locking bolt, including: a nut, a threaded rod, and a compensator;

[0007] The nut is provided with an internal thread, and the screw is provided with an external thread that matches the internal thread;

[0008] The internal thread and the external thread include mutually matching thread units. The thread units at the matching positions of the internal thread and the external thread are different. The thread unit includes multiple first thread units and multiple second thread units. Each second thread unit includes a thread groove. The thread groove includes a slot structure with axial height. The first thread unit includes a thread structure adapted to the slot structure. When the thread structure is screwed into the pre-tightened state along the thread groove, a bearing structure is formed between the slot structure and the thread structure. The bearing structure provides a force to the nut that is opposite to the pre-tightening force. Furthermore, the slot structure and the thread structure form a self-locking structure through the mating surface in the screwing direction of the nut.

[0009] The compensator is disposed between the nut and the workpiece to be fastened, and when the nut and the compensator are screwed into a preset position, the compensator generates an axial displacement in a predetermined direction. At the preset position, the gap between the compensator and the workpiece to be fastened is less than the axial lifting height of the thread structure between two adjacent slot structures. The preset direction is the rotation direction away from the nut, and the axial displacement is not less than the stroke required for the slot structure and the thread structure to reach the pre-tightened state.

[0010] Optionally, the groove structure includes a first fixing part, and the thread structure includes a second fixing part;

[0011] When the threaded structure is screwed into the pre-tightened state along the thread groove, the first fixing part and the second fixing part constitute the bearing structure and the self-locking structure within a predetermined fitting range, and the first fixing part engages with the second fixing part in the screwing direction of the nut.

[0012] Optionally, the groove structure further includes a first force-bearing part, and the thread structure further includes a second force-bearing part;

[0013] When the threaded structure is screwed into the pre-tightened state along the thread groove, the first force-bearing part and the second force-bearing part constitute the bearing structure within a predetermined contact range, and the first fixing part and the second fixing part constitute the self-locking structure within a predetermined contact range, and the first force-bearing part and the second force-bearing part are locked in the screwing direction of the nut.

[0014] Optionally, the first threaded unit includes a first upper thread and a first lower thread, and the second threaded unit includes a second upper thread and a second lower thread;

[0015] The first and second upper thread lines are line segments arranged parallel to the screwing direction, which are used to provide screwing guidance for the nut;

[0016] The second lower thread includes a second horizontal bearing section and a first convex section and a second convex section disposed at both ends of the second horizontal bearing section. The second convex section is disposed along the screwing direction of the nut and forms a preset angle with the second lower thread. Along the screwing direction of the nut, the axial height of the second convex section is greater than the axial height of the first convex section. The first lower thread and the second lower thread are configured to cooperate.

[0017] The line connecting the top of the first protrusion and the top of the second protrusion is set parallel to the second upper thread line;

[0018] The threaded groove is formed between the second upper thread and the second lower thread of each second threaded unit. The second horizontal bearing section serves as the first force-bearing part, and the first convex section and the second convex section serve as the first fixing part. The second horizontal bearing section cooperates with the first lower thread to form the bearing structure. The first convex section and the second convex section cooperate with the first lower thread to form the mating surface.

[0019] The thread structure is formed between the first upper thread and the first lower thread of each first thread unit, and the minimum axial width of the thread groove is greater than the maximum axial width of the thread structure.

[0020] Optionally, the angle between the first upper thread and the horizontal plane, and the angle between the second upper thread and the horizontal plane, are both equal to the thread helix angle of the self-locking bolt.

[0021] Optionally, the included angle between the first convex segment and the second convex segment between two adjacent second threaded units is 15° to 180°.

[0022] Optionally, the compensator is sleeved on the screw and rotates relative to the screw. Compensation structures are provided on the end faces of the compensator and the nut that are close to each other. The compensation structures compensate for the axial displacement of the nut after the nut reaches the pre-tightened state.

[0023] Optionally, the compensation structure includes a first compensation structure disposed on the end face of the nut near the compensator and a second compensation structure disposed on the end face of the compensator near the nut. Both the first compensation structure and the second compensation structure are double-ring structures, including an inner ring and an outer ring. The inner diameter of the inner ring is larger than the major diameter of the screw, and the shape of the outer ring is adapted to the shape of the nut. Lifting structures for lifting the compensator are provided on the end faces of the inner ring and the outer ring, so that the compensator can be displaced axially on the screw.

[0024] Optionally, the lifting structure includes multiple lifting zones perpendicular to the screw axis;

[0025] Both the inner and outer rings are provided with lifting zones that are distributed circumferentially and whose height increases in a stepped manner. Adjacent lifting zones are connected by an inclined transition surface to guide the compensator to move relative to each other in the lifting direction. No inclined transition surface is provided between the highest and lowest lifting zones, thus forming a stop surface to prevent the compensator from moving relative to each other in the opposite direction.

[0026] Optionally, the total lifting stroke of the lifting areas of the inner ring and the outer ring is equal, and is greater than or equal to the axial lifting height of a single second threaded unit or a single first threaded unit.

[0027] Optionally, the lifting areas with the same axial height in the inner ring and the outer ring are offset by 180° in the circumferential direction of the compensator and the nut.

[0028] Optionally, the number of lifting zones of the compensator is set according to the nut compensation accuracy requirements.

[0029] Secondly, embodiments of this application provide a fastening device, which is provided with the aforementioned self-locking bolt.

[0030] In this embodiment, the self-locking bolt includes a nut, a screw, and a compensator. A first threaded unit and a second threaded unit are provided on the nut and screw. The first threaded unit includes a threaded structure, and the second threaded unit includes a threaded groove. The threaded groove includes a slotted structure adapted to the threaded structure. As the nut screws along the screw, the threaded structure of the nut screws into the threaded groove. When the nut reaches a pre-tightened state with the workpiece to be fastened through the compensator, the threaded structure of the nut and the slotted structure of the screw fit tightly together to form a mating surface. Furthermore, a load-bearing structure is formed between the two, providing a force opposite to the pre-tightening force to the nut. The slotted structure and the threaded structure also form a self-locking structure through the mating surface. Thus, by combining the load-bearing structure with the mechanical self-locking structure, complete self-locking of the bolt and fixation to the workpiece to be fastened are achieved, ensuring that external impact cannot be converted into a rotational torque that causes loosening, significantly improving the stability of the bolt.

[0031] This application eliminates the "wedge effect" from the thread geometry, and its anti-loosening principle is superior to all existing "patchwork" technologies.

[0032] This application combines the self-locking of the threaded pair with the anti-loosening effect of the compensator's plane contact, resulting in extremely reliable performance under severe vibration and impact.

[0033] All components in this application are mechanical structures that will not be damaged after disassembly and can be reused multiple times; the stroke compensator solves the problem of precise pre-tightening of discrete thread units and realizes the feasibility of engineering applications.

[0034] Compared to complex mechanical anti-loosening solutions, this application features a core structure consisting of a bolt, nut, and compensator—a three-piece design that is easy to manufacture and install. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the self-locking bolt structure of the present invention;

[0036] Figure 2 This is a schematic diagram of the self-locking bolt installation state structure of the present invention;

[0037] Figure 3 This is a schematic diagram of the compensator structure of the present invention;

[0038] Figure 4 This is a schematic diagram of the nut structure of the present invention;

[0039] Figure 5 This is a schematic diagram of the flattened (relative position of the thread structure and the thread groove during the screwing process) structure of the self-locking bolt thread unit of the present invention;

[0040] Figure 6 This is a schematic diagram of the self-locking bolt thread unit of the present invention (the relative position of the thread structure and the thread groove after being screwed into place);

[0041] Figure 7 This is a schematic diagram of the flattened (relative position when the thread structure screws over the peak of the slotted structure) structure of the self-locking bolt thread unit of the present invention.

[0042] Figure 8 This is a schematic diagram of the screw ("V-shaped" groove structure) of the self-locking bolt of the present invention;

[0043] Figure 9 This is a schematic diagram of the unfolded state of the screw and nut ("V-shaped" groove structure) of the self-locking bolt of the present invention;

[0044] Figure 10 This is a schematic diagram of the thread groove structure of a bolt according to an embodiment of the present invention;

[0045] Figure 11 This is a schematic diagram of the self-locking bolt structure from a second perspective according to an embodiment of the present invention;

[0046] Figure 12 This is a third-view structural schematic diagram of a self-locking bolt according to an embodiment of the present invention;

[0047] Figure 13 This is a schematic diagram of a screw structure according to an embodiment of the present invention;

[0048] Figure 14 To and Figure 13 A schematic diagram of a nut structure that is compatible with a screw.

[0049] Explanation of reference numerals in the attached figures:

[0050] 1. Nut; 2. Screw; 3. Compensator; 31. Inner ring; 32. Outer ring; 33. Lifting area; 34. Inclined transition surface; 35. Stop surface; 4. Guide groove; 5. Insertion structure; 51. First fixing part; 52. First force-bearing part; 6. Thread structure; 61. Second fixing part; 62. Second force-bearing part; 7. First upper thread; 8. First lower thread; 81. Third convex section; 82. Fourth convex section; 83. First horizontal bearing section; 9. Second upper thread; 10. Second lower thread; 101. First convex section; 102. Second convex section; 103. Second horizontal bearing section; 11. Workpiece to be fastened; 12. Bearing structure; 13. Self-locking structure; 14. Bolt head; 15. Thread groove. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0052] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0053] The application scenarios of this application will be described below.

[0054] Bolted connections are the most basic and crucial connection method in mechanical equipment, and their reliability directly affects the overall safety and stable operation of the equipment. Under dynamic operating conditions such as vibration, impact, and temperature fluctuations, traditional threaded connections are prone to loosening and failure due to preload decay.

[0055] The root cause of loosening in conventional threads is the "wedge effect." Conventional threads consist of continuous helical lines with a fixed slope. After the nut is tightened, the threaded contact surface forms an inclined plane. When the connection point is subjected to axial impact, the impact force is decomposed into two components along this inclined plane: a clamping force perpendicular to the inclined plane, and a separating force parallel to the inclined plane that drives the nut to rotate. The latter is the "wedge effect" that leads to loosening.

[0056] Under prolonged high-load impact and vibration, the impulse of the instantaneous impact load will generate a large tangential component on the threaded contact surface. This component is sufficient to disrupt the static equilibrium maintained by the friction of the threaded surface, causing microscopic relative sliding on the threaded contact surface. Due to the presence of the inclined plane, this minute sliding will directly translate into the reverse rotation and axial displacement of the nut. Under the continuous action of the axial reaction force of the preload, this loosening effect of "sliding-rotation-displacement" will accumulate in a directional manner, eventually leading to complete failure of the connection.

[0057] Among related technologies, the mainstream anti-loosening technologies can be divided into friction anti-loosening (such as spring washers and double nuts), mechanical anti-loosening (such as cotter pins and locking washers), and permanent anti-loosening (such as welding and bonding). These methods are all "patchwork" improvements on the "ramp" model (i.e., traditional threads) with inherent design flaws, and fail to change the mechanical properties of the thread itself geometrically. Therefore, they generally have limitations such as increased structural complexity, increased manufacturing costs, non-reusability, or sensitivity to specific working conditions.

[0058] The self-locking bolt and fastening device provided in this application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] This embodiment provides a self-locking bolt, such as Figures 1-2 , Figures 5-7 and Figures 10-12 As shown, the self-locking bolt includes: a nut 1, a screw 2, and a compensator 3. The nut 1 has an internal thread, and the screw 2 has an external thread that matches the internal thread. The internal and external threads include matching thread units. The matching positions of the thread units for the internal and external threads are different. Each thread unit includes multiple first thread units and multiple second thread units. Each second thread unit includes a thread groove. The thread groove includes a slotted structure 5 with axial height. The first thread unit includes a threaded structure 6 that matches the slotted structure 5. When the threaded structure 6 is screwed into the thread groove to the pre-tightened state, the slotted structure 5 and the threaded structure... A bearing structure 12 is formed between the 6, which provides a force to the nut 1 in the opposite direction to the preload. A self-locking structure 13 is formed between the groove structure 5 and the thread structure 6 through the mating surface in the screwing direction of the nut 1. The compensator 3 is set between the nut 1 and the workpiece 11 to be fastened. When the nut 1 and the compensator 3 are screwed in to the point that the gap between the compensator 3 and the workpiece 11 to be fastened is less than the axial lifting height of the thread structure 6 between two adjacent groove structures 5, the compensator 3 rotates and generates an axial displacement in the direction away from the nut 1. The axial displacement is not less than the stroke required for the groove structure 5 and the thread structure 6 to reach the preload state.

[0060] In the embodiments of this application, the screw 2 and the nut 1 are connected by internal and external threads, such as... Figure 6 As shown, the external and internal threads are divided into multiple first thread units and second thread units by multiple vertical lines. Side A is the starting end of the first thread unit and the second thread unit, and side B is the ending end of the first thread unit and the second thread unit. The external thread can be configured as multiple second thread units connected by their starting ends and ending ends in sequence, that is, connected end to end and spirally arranged in the bolt axial direction to form a complete and continuous thread structure. The internal thread can be configured as multiple first thread units connected end to end in sequence and spirally arranged in the inner axial direction of the nut to form a complete and continuous thread structure.

[0061] Specifically, the second threaded unit includes a threaded groove structure, which includes a groove structure 5 having a height in the axial direction of the screw 2 and a guide groove 4 for the threaded tooth structure 6 to be screwed in. The first threaded unit includes a threaded tooth structure 6, the shape of which is adapted to the groove structure 5. The threaded tooth structure 6 can be interlocked with the groove structure 5 to form a self-locking structure 13, so that the nut no longer displaces in the axial direction and in the screwing direction.

[0062] For example, the screwing direction of the nut described above is as follows: Figure 1 The direction indicated by arrow a shown is and Figure 7 The direction indicated by arrow b is the rotation direction of the compensation displacement of the above-mentioned compensator. Figure 1 The direction indicated by arrow e is as follows: the axial direction of the aforementioned screw 2 is... Figure 1 The arrow d and Figure 7 The direction indicated by arrow c.

[0063] It is understandable that the above-mentioned threaded groove setting method is used to ensure that the threaded structure 6 can be screwed into the guide groove 4 of the threaded groove, and when the threaded structure 6 is screwed into a certain height, it can be engaged with the grooved structure 5, thereby achieving self-locking. In the self-locking state, the nut can no longer rotate.

[0064] Furthermore, the aforementioned groove structure 5 is designed to form a load-bearing structure in a pre-tightened state (in which the nut 1 needs to generate an interaction force with the workpiece 11 to be fastened). Specifically, the load-bearing structure ensures that when the groove structure 5 and the thread structure 6 are engaged, the groove structure 5 generates an axial supporting force on the thread structure 6 (opposite to the direction of the pre-tightening force of the nut 1), and the direction of the axial supporting force is as follows: Figure 1 The arrow d indicates the direction; simultaneously, the two ends of the slotted structure 5 and the threaded structure 6 form a self-locking structure 13 in the screwing direction of the nut 1 to prevent the nut 1 from retracting. For example, the nut 1 rotates in the opposite direction to the screwing direction, wherein the opposite direction to the screwing direction is... Figure 1 The direction opposite to the middle arrow 'a'.

[0065] For example, such as Figure 1As shown, the screw 2 can be a structure with a bolt head 14, and the workpiece is fixed by the nut 1 and the bolt head 14.

[0066] For example, the aforementioned screw can be a structure without a bolt head. Specifically, the screw can also be a single cylindrical structure, and the thread matching the screw can be a unidirectional thread, or the thread on the screw can be divided into two regions along the axial direction with opposite thread directions in the two regions. Each region is equipped with a nut and a compensator, and the workpiece is fixed by the nuts in the two regions.

[0067] For example, the first and second thread units mentioned above can be configured according to actual working conditions, such as... Figure 13 and Figure 14 As shown, the first threaded unit can be mounted on the screw 2, and the second threaded unit can be mounted on the nut 1; normally, the first threaded unit can also be mounted on the nut 1, and the second threaded unit can be mounted on the screw 2. Figure 1 In the process, the first threaded unit is disposed on the nut 1, and the second threaded unit is disposed on the screw 2.

[0068] In other embodiments, when the first threaded unit is disposed on the screw 2 and the second threaded unit is disposed on the nut 1, the positions of the slotted structure 5 and the threaded structure 6 are interchanged, but the cooperation relationship between the two and the principle of self-locking through the self-locking structure 13 are the same. This application embodiment is applicable to scenarios where the nut 1 is large and the screw 2 is small, such as the connection of slender screws 2 in large equipment.

[0069] For example, the aforementioned groove structure 5 can at least allow half of the axial height of the thread structure 6 to be embedded in the groove structure 5. At the same time, the load-bearing structure in the groove structure 5 can at least provide the thread structure 6 with the axial preload of the screw 2. When subjected to external impact, the impact force can be prevented from being converted into a rotational torque that causes the nut 1 to loosen.

[0070] Example 1: such as Figure 6 As shown, the dashed box indicates the load-bearing structure 12 and the dashed box indicates the self-locking structure 13. Specifically, the load-bearing structure 12 can be used to support the threaded structure 6. On the load-bearing surface of the load-bearing structure 12, there is only axial force on the screw 2, and no tangential force on the screw 2. The self-locking structure 13 is located on both sides of the load-bearing structure 12 and can lock the threaded structure 6 within the range of the load-bearing structure 12, further ensuring the stability of the connection between the nut 1 and the screw 2.

[0071] For example, such as Figure 2As shown, the compensator 3 is located on the side of the nut 1 near the workpiece 11 to be fastened, that is, the compensator 3 is located on the top of the nut 1. The compensator 3 gradually approaches the workpiece 11 to be fastened as the nut 1 is screwed in. When the nut 1 rotates to be close to the workpiece 11, if the gap between the compensator 3 and the workpiece 11 is insufficient to lift the nut 1 from the previous slot structure 5 to the next slot structure 5 (the compensator 3 lifts with the nut 1), that is, when the gap between the compensator 3 and the workpiece 11 to be fastened is less than the axial lifting height of the nut 1 between two adjacent slot structures 5, the nut 1 and the compensator 3 can no longer lift synchronously, that is, the nut cannot rotate. At this time, by continuing to rotate the compensator 3, the compensator 3 will generate axial displacement (elongation) in the axial direction of the screw 2, and press against the nut 1 and the workpiece 11 to be fastened, generating a preload force between the nut 1 and the workpiece 11 to be fastened, so that the nut 1 and the screw 2 are locked.

[0072] Understandably, during the actual installation process, nut 1 is screwed in together with compensator 3 until compensator 3 is in contact with the workpiece 11 to be fastened. This means that nut 1 can no longer be screwed in. At this point, nut 1 is slightly reversed so that the thread structure 6 and the groove structure 5 are locked together. During this process, nut 1 and compensator 3 have a small axial displacement in the direction away from the workpiece 11 to be fastened. Then, by rotating compensator 3 separately, the axial height of compensator 3 is adjusted to lock bolt 2 and nut 1.

[0073] For example, the horizontal inclination angle of the first upper thread 7 or the second upper thread 9 can be set to 5°. Since the self-locking bolt in this embodiment does not need to rely on the friction force and preload of the thread pair to maintain the fastening condition, the horizontal inclination angle of the thread does not need to consider the friction equivalent, and only the thread efficiency and processing cost need to be considered. The horizontal inclination angle in this embodiment can be set to ≤40°.

[0074] In this embodiment, the self-locking bolt includes a nut 1, a screw 2, and a compensator 3. A first thread unit and a second thread unit are provided on the nut 1 and screw 2. The first thread unit includes a threaded structure 6, and the second thread unit includes a threaded groove 15. The threaded groove 15 includes a slotted structure 5 adapted to the threaded structure 6. During the screw 1's rotation along the screw 2, the threaded structure 6 of the nut 1 rotates within the threaded groove 15. When the nut 1 reaches a pre-tightened state with the workpiece 11 to be fastened via the compensator 3, the threaded structure 6 of the nut 1 and the slotted structure 5 of the screw 2 fit tightly together to form a mating surface. A bearing structure 12 is formed between them, providing a force opposite to the pre-tightening force to the nut 1. Furthermore, a self-locking structure 13 is formed between the slotted structure 5 and the threaded structure 6 through the mating surface. Thus, by combining the bearing structure 12 with the mechanical self-locking structure 13, complete self-locking of the bolt and fixation to the workpiece 11 to be fastened are achieved, ensuring that external impact cannot be converted into a rotational torque that causes loosening, significantly improving the bolt's stability.

[0075] Optionally, in embodiments of this application, such as Figure 8 and Figure 9 As shown, the groove structure 5 includes a first fixing part 51, and the thread structure 6 includes a second fixing part 61. When the thread structure 6 is screwed into the thread groove to the pre-tightened state, the first fixing part 51 and the second fixing part 61 form a load-bearing structure and a self-locking structure 13 within a predetermined fitting range. The first fixing part 51 engages with the second fixing part 61 in the screwing direction of the nut 1.

[0076] Understandably, for some small-sized bolts, the load is generally small. For the groove structure 5 and the thread structure 6, a first fixing part 51 and a second fixing part 61 are respectively provided. The first fixing part 51 constitutes the groove structure, and the second fixing part 61 constitutes the thread structure. The screw 2 and the nut 1 are self-locked by the first fixing part 51 and the second fixing part 61. It should be noted that the small-sized bolts mentioned in this embodiment refer to bolts with an M10 size or smaller.

[0077] Optionally, in embodiments of this application, such as Figure 1 -like Figure 7 As shown, the groove structure 5 also includes a first force-bearing part 52, and the thread structure 6 also includes a second force-bearing part 62. When the thread structure 6 is screwed into the thread groove 15 to the pre-tightened state, the first force-bearing part 52 and the second force-bearing part 62 form a bearing structure within a predetermined fitting range, and the first fixing part 51 and the second fixing part 61 form a self-locking structure 13 within a predetermined fitting range, and the first force-bearing part 52 and the second force-bearing part 62 are locked in the screwing direction of the nut 1.

[0078] Understandably, in this embodiment, by adding a first force-bearing part 52 of the groove structure 5 and a second force-bearing part 62 of the thread structure 6, the first force-bearing part 52 and the second force-bearing part 62 constitute axial support for the nut 1, and the first fixing part 51 and the second fixing part 61 constitute a limit in the screwing direction of the nut, forming a self-locking structure as a whole.

[0079] This allows the self-locking structure 13 to be applicable to bolts with large loads and large specifications, where large specifications refer to bolts of M10 and above.

[0080] Optionally, in embodiments of this application, such as Figures 1-2 , Figures 5-7 As shown, the first threaded unit is disposed on the nut 1, and the second threaded unit is disposed on the screw 2. The first threaded unit includes a first upper thread 7 and a first lower thread 8, and the second threaded unit includes a second upper thread 9 and a second lower thread 10. The first upper thread 7 and the second upper thread 9 are line segments arranged parallel to the screwing direction of the nut 1, which are used to provide screwing guidance for the nut 1.

[0081] Specifically, the first upper thread 7 is set as the internal thread structure of the nut 1, and the second upper thread 9 is set as the external thread structure of the bolt. When the nut 1 is engaged with the screw 2, the first upper thread 7 and the second upper thread 9 form the guide line for the nut 1 to screw around the screw 2. The first upper thread 7 and the second upper thread 9 are set at the same angle, and the horizontal inclination angle (the angle between the first upper thread 7 and the second upper thread 9 and the horizontal plane) is the same as the thread helix angle of the bolt.

[0082] Furthermore, the second lower thread 10 includes a second horizontal bearing section 103 and a first protrusion 101 and a second protrusion 102 disposed at both ends of the second horizontal bearing section 103. The second protrusion 102 is disposed along the screwing direction of the nut 1 and forms a preset angle with the second lower thread 10. Along the screwing direction of the nut 1, the axial height of the second protrusion 102 is greater than the axial height of the first protrusion 101. The first lower thread 8 and the second lower thread 10 are fitted together. A thread groove is formed between the second upper thread 9 and the second lower thread 10 of each second thread unit. The second horizontal bearing section 103 serves as the first force-bearing part 52, and the first protrusion 101 and the second protrusion 102 serve as the first fixing part 51. The second horizontal bearing section 103 and the first lower thread 8 cooperate to form a bearing structure. The first protrusion 101 and the second protrusion 102 cooperate with the first lower thread 8 to form a mating surface.

[0083] Specifically, the first fixing part 51 is composed of a second threaded line 10, which includes a first protrusion 101 and a second protrusion 102. The second fixing part 61 is composed of a first threaded line 8, which includes a third protrusion 81 and a fourth protrusion 82.

[0084] For example, for a bolt that achieves self-locking solely through the first fixing part 51 and the second fixing part 61, the first protrusion 101 and the second protrusion 102 form a "V-shaped" groove structure 5, and the third protrusion 81 and the fourth protrusion 82 form an "inverted V-shaped" thread structure 6 that matches the groove structure 5. Furthermore, the axial height of the second protrusion 102 is greater than the axial height of the first protrusion 101, and the axial height of the fourth protrusion 82 is greater than the axial height of the third protrusion 81, forming a groove structure 5 that is inclined along the screwing direction of the nut 1. At the same time, the thread structure can be locked on both sides of the thread structure, thereby achieving self-locking between the nut and the bolt.

[0085] For example, the locking configuration of the slotted structure 5 and the threaded structure 6 is as follows: the inclined first protrusion 101 and the second protrusion 102 support the third protrusion 81 and the fourth protrusion 82 of the threaded structure 6. The support of the first protrusion 101 and the second protrusion 102 on the threaded structure 6 forms a force opposite to the preload of the nut 1. At the same time, the two also form a self-locking structure on both sides of the threaded structure 6. After the compensator 3 completes the compensation, the threaded structure 6 is locked by the first protrusion 101 and the second protrusion 102 on both sides, thus completing the self-locking.

[0086] For example, for a bolt that self-locks the screw 2 and nut 1 through the aforementioned groove structure 5 with a bearing structure, the first protrusion 101 and the second protrusion 102 are at a preset angle and are respectively set at both ends of the second horizontal bearing section 103, forming a groove structure 5 with a horizontal groove bottom. The third protrusion 81 and the fourth protrusion 82 are set at both ends of the first horizontal bearing section 83, forming a thread structure 6 that is compatible with the groove structure 5. The height of the second protrusion 102 in the bolt axial direction is greater than the height of the first protrusion 101 in the bolt axial direction. The groove structure 5 plays a guiding role along the screwing direction of the nut. The groove structure 5 can support the bottom of the thread structure 6 and simultaneously lock the thread structure 6 on both sides, thus completing the self-locking of the nut 1 and the screw 2.

[0087] In the embodiments of this application, the first force-bearing part 52 and the first fixing part 51 are composed of a second threaded line 10. In addition to the first protrusion 101 and the second protrusion 102, the second threaded line 10 is also provided with a second horizontal bearing section 103 located between the first protrusion 101 and the second protrusion 102. The second horizontal bearing section 103 is arranged in a horizontal direction, and the bottom ends of the first protrusion 101 and the second protrusion 102 are respectively connected to the two ends of the second horizontal bearing section 103. The first protrusion 101 and the second protrusion 102 are arranged at a preset angle with the first horizontal bearing section 103.

[0088] For example, the preset angle between the first convex segment 101 and the second horizontal bearing segment 103 is 135°, and the preset angle between the second convex segment 102 and the second horizontal bearing segment 103 is 45°.

[0089] For example, the horizontally arranged second horizontal bearing section 103 serves as the first force-bearing part 52, and the inclined first protrusion 101 and second protrusion 102 serve as the first fixing part 51. The second force-bearing part 62 and the second fixing part 61 are composed of a first lower thread 8. In addition to the third protrusion 81 and the fourth protrusion 82, the first lower thread 8 also has a first horizontal bearing section 83. The first horizontal bearing section 83 is arranged in a horizontal direction, and the bottom ends of the third protrusion 81 and the fourth protrusion 82 are respectively connected to the two ends of the first horizontal bearing section 83. The third protrusion 81 and the fourth protrusion 82 are arranged at a preset angle with the first horizontal bearing section 83. The first lower thread 8 and the second lower thread 10 are configured to be compatible with each other. The first horizontal bearing section 83 serves as the second force-bearing part 62, and the third protrusion 81 and the fourth protrusion 82 serve as the second fixing part 61.

[0090] Furthermore, the aforementioned first force-bearing part 52, first fixing part 51, second force-bearing part 62, and second fixing part 61 constitute a self-locking structure 13 for the bolt. Specifically, the first force-bearing part 52 and the second force-bearing part 62, when the nut 1 and screw 2 are pre-tightened, form a bearing surface perpendicular to the axial direction of the screw 2 by fitting together. Simultaneously, this bearing surface also provides a force to the nut 1 in the opposite direction to the pre-tightening force. When the nut 1 and screw 2 are locked, the threads between the nut 1 and screw 2 are engaged through the first force-bearing part 52 and the second force-bearing part 62. When the bolt is subjected to impact or vibration, the first force-bearing part 52 and the second force-bearing part 62 are perpendicular to the axial pre-tightening force, therefore no component force is generated in the screwing direction of the nut 1. The screwing direction of the nut 1 is as follows... Figure 1 The direction indicated by the middle arrow 1 can reduce the tangential force of the retraction rotation on nut 1.

[0091] For example, the first fixing part 51 and the first force-receiving part 52 are set at a preset angle, and the second fixing part 61 and the second force-receiving part 52 are set at a preset angle. The preset angle is less than 180°. A locking structure is formed at both ends of the first force-receiving part 52 and the second force-receiving part 62 to further prevent the nut 1 from rotating in the screwing direction. At the same time, the first fixing part 51 and the second fixing part 61 are set at an angle, which can also serve as a guide structure for the screwing of the nut 1, and guide the screwing of the nut 1 in conjunction with the first upper thread 7 and the second lower thread 10.

[0092] For example, the second horizontal bearing section 103 described above is configured as a structure parallel to the horizontal plane, with a first protrusion 101 and a second protrusion 102 disposed at both ends of the second horizontal bearing section 103. Specifically, the first protrusion 101 is disposed on the screw-in end side of the threaded structure 6 of the second horizontal bearing section 103, such as... Figure 5 As shown, side A is the screw-in end of the threaded structure 6, and the second protrusion 102 is located on the screw-out end of the second horizontal bearing section 103, as shown. Figure 5 As shown, side B is the screw-out end of the threaded structure 6, and a preset angle is provided between the first protrusion 101 and the second protrusion 102 and the second horizontal bearing section 103. At the same time, the first lower thread 8 is set to a shape that matches the second lower thread 10, so that the structure formed by the first lower thread 8 can be embedded in the groove structure 5 formed by the second lower thread 10 and completely fit with the groove structure 5 to form a self-locking structure.

[0093] In the embodiments of this application, the line connecting the top end of the first protrusion 101 and the top end of the second protrusion 102 is arranged parallel to the second upper thread line 9.

[0094] For example, the arrangement of the first protrusion 101 and the second protrusion 102 requires that the axial height of the second protrusion 102 be higher than that of the first protrusion 101, so that a structure parallel to the second upper thread line 9 is formed between the top of the first protrusion 101 and the top of the second protrusion 102, so that a helical lifting force is generated during the rotation of the nut 1, and the nut 1 is prevented from being unable to rise due to the horizontally arranged second horizontal bearing section 103.

[0095] For example, the angle between the line connecting the top of the first convex segment 101 and the top of the second convex segment 102 and the horizontal plane can be set to 5°.

[0096] In the embodiments of this application, a thread structure 6 is formed between the first upper thread line 7 and the first lower thread line 8 of each first thread unit, and the minimum axial width of the thread groove 15 is greater than the maximum axial width of the thread structure 6.

[0097] Specifically, the second upper thread 9 and the second lower thread 10 together form a threaded groove 15 structure. The second lower thread 10 forms a slotted structure 5. Above the slotted structure 5, a guide groove 4 structure is formed with the second upper thread 9. The threaded structure 6 is composed of the first upper thread 7 and the first lower thread 8. The specific shape of the threaded structure 6 is adapted to the slotted structure 5. At the same time, the maximum height of the threaded structure 6 in the axial direction of the screw 2 is not less than the minimum height of the guide groove 4 in the axial direction of the screw 2, so that the nut 1 can be screwed into the guide groove 4 through the threaded structure 6. At the same time, the threaded structure 6 can be locked into the slotted structure 5 in the pre-tightened position to complete the self-locking of the nut 1 and the screw 2.

[0098] Optionally, in the embodiments of this application, the included angle between the first protrusion 101 and the second protrusion 102 between two adjacent second threaded units is 15°~180°.

[0099] For example, the first protrusion 101 and the second protrusion 102 mentioned above serve as the self-locking structure 13 of the nut 1. The first protrusion 101 can serve as a limiting member for restricting the left and right rotation of the thread structure 6. The second protrusion 102 not only needs to serve as a limiting member for restricting the left and right rotation of the thread structure 6, but also needs to serve as a guide member with a guiding function. The second protrusion 102 has a certain tilt angle so that the thread structure 6 can be screwed along the tilted second protrusion 102 and the second upper thread line 9 during the screwing process of the nut 1.

[0100] Specifically, the angle between the first protrusion 101 and the second protrusion 102 must meet the screw-in lifting angle of the nut 1. At the same time, when the pre-tightening state is reached, the angle between the first protrusion 101 and the second protrusion 102 can play a certain locking role to prevent the nut 1 from retracting due to the angle being too small.

[0101] For example, the smaller the angle between the first protrusion 101 and the second protrusion 102 is (less than 180°), the better the limiting effect on the screwing direction of the nut 1. The larger the angle between the first protrusion 101 and the second protrusion 102 is (greater than 15°), the smaller the impact on the screwing of the nut 1. The optimal angle between the first protrusion 101 and the second protrusion 102 is 90°.

[0102] Optionally, in embodiments of this application, such as Figures 1-4 As shown, the compensator 3 is sleeved on the screw 2 and rotates relative to the screw 2. Compensation structures are provided on the end faces of the compensator 3 and the nut 1 that are close to each other. The compensation structures compensate for the axial displacement of the nut 1 after the nut 1 reaches the pre-tightened state.

[0103] Specifically, the compensator 3 is sleeved on the screw 2, and there is a gap between the compensator 3 and the screw 2. The rotation of the compensator 3 does not interfere with the screw 2. When installing the nut 1, the compensator 3 is placed between the nut 1 and the workpiece 11 to be fastened. The compensator 3 on the screw 2 can gradually approach the workpiece 11 to be fastened as the nut 1 is screwed in, until the compensator 3 contacts the workpiece 11 to be fastened. At this time, the thread structure of the nut 1 will no longer cross the axial highest point of the groove structure 5 of the second thread unit, and the thread structure will fall a certain distance, so that the nut 1 and the groove structure 5 are completely fitted. At this time, the nut 1 no longer rotates, and displacement (elongation) is generated in the axial direction of the screw 2 through the compensation structure on the compensator 3. The top and bottom of the compensator 3 respectively press against the nut 1 and the workpiece 11 to be fastened and lock them, so that the thread structure 6 of the nut 1 is embedded in the groove structure 5.

[0104] For example, the outer circumferential surface of the compensator 3 can be set to the same shape and size as the nut 1, and can be adjusted by the nut adjustment mechanism, for example, by a wrench adapted to the nut; the outer circumferential surface of the compensator 3 can also be set to a different shape and size than the nut 1, for example, a protruding structure can be set on the outer circumferential surface of the compensator 3 to facilitate individual adjustment of the compensator 3 during compensation.

[0105] For example, the protruding structure described above can be a lever that extends radially along the outer periphery of the compensator 3. The lever is fixedly connected to the compensator 3, and the compensator 3 can be easily adjusted by rotating the lever.

[0106] For example, the protruding structure described above is detachably connected to the compensator 3.

[0107] For example, a threaded blind hole is provided on the outer periphery of the compensator 3, and a protruding structure is disposed in the threaded blind hole and threadedly connected to the threaded blind hole. In this way, when the compensator 3 needs to be adjusted, the above-mentioned protruding structure can be installed at the same time.

[0108] For example, after nut 1 is locked, the protruding structure can be removed to prevent the compensator 3 from rotating in the opposite direction due to accidental contact with the protruding structure, which would shorten the compensation displacement, cause the self-locking of nut 1 to fail, loosen nut 1, and affect the fixing effect of nut 1.

[0109] Optionally, in embodiments of this application, such as Figures 1-4 As shown, the compensation structure includes a first compensation structure disposed on the end face of the nut 1 near the compensator 3 and a second compensation structure disposed on the end face of the compensator 3 near the nut 1. Both the first and second compensation structures are double-ring structures, including an inner ring 31 and an outer ring 32. The inner diameter of the inner ring 31 is larger than the major diameter of the screw 2. The shape of the outer ring 32 is adapted to the shape of the nut 1. Lifting structures for lifting the compensator 3 are provided on the end faces of the inner ring 31 and the outer ring 32 so that the compensator 3 can be displaced axially in the screw 2.

[0110] Specifically, the first compensation structure and the second compensation structure mentioned above are set to the same structure. The first compensation structure and the second compensation structure are set on the end face of the compensator 3 and the end face of the nut 1. The first compensation structure and the second compensation structure can be set as a double-ring structure. The compensator 3 is lifted by the lifting structure on the inner ring and the outer ring. The double-ring structure includes an inner ring 31 and an outer ring 32. A circular through hole is provided in the middle of the compensator 3, and the diameter of the circular through hole is slightly larger than the major diameter of the screw 2, so that the compensator 3 can freely rotate around the screw 2 and move up and down. The lifting structure of the end face of the compensator 3 and the end face of the nut 1 is a double-ring structure, which divides the end faces of the two into two rings, namely the inner ring 31 and the outer ring 32. The inner ring 31 is bounded by the central circular hole, and the outer ring 32 is bounded by the outer periphery of the compensator 3 / nut 1. Both the inner ring 31 and the outer ring 32 are provided with lifting structures, and the lifting structures of the inner ring 31 and the outer ring 32 are set at a preset angle.

[0111] Optionally, in embodiments of this application, such as Figures 1-4 As shown, the lifting structure includes multiple lifting zones 33 perpendicular to the axial direction of the screw 2; both the inner ring 31 and the outer ring 32 are provided with lifting zones 33 distributed circumferentially and with increasing height in a stepped manner. Adjacent lifting zones 33 are connected by an inclined transition surface 34 to guide the compensator 3 to move relative to each other in the lifting direction. No inclined transition surface 34 is provided between the highest lifting zone 33 and the lowest lifting zone 33, thus forming a stop surface 35 to prevent the compensator 3 from moving relative to each other in the opposite direction.

[0112] For example, multiple lifting areas 33 are provided, dividing the end face of the compensator 3 / nut 1 into multiple arc-shaped areas. In the same ring, the multiple lifting areas 33 are arranged in a stepped manner along the circumferential height. Furthermore, in the inner and outer rings, lifting areas 33 of the same height are staggered, so that when the nut 1 and the compensator 3 are initially connected, the inner and outer ring structures form a nested structure.

[0113] For example, when the nut 1 and the compensator 3 are initially aligned, the highest lifting area 33 of the inner ring 31 on the compensator 3 corresponds to the lowest lifting area 33 of the inner ring 31 on the nut 1, and the lowest lifting area 33 of the inner ring 31 on the compensator 3 corresponds to the highest lifting area 33 of the inner ring 31 on the nut 1. The highest lifting area 33 of the outer ring 32 on the compensator 3 corresponds to the lowest lifting area 33 of the outer ring 32 on the nut 1, and the lowest lifting area 33 of the outer ring 32 on the compensator 3 corresponds to the highest lifting area 33 of the outer ring 32 on the nut 1. Other lifting areas 33 with different heights also correspond one-to-one, so that the initial length of the joint between the nut 1 and the compensator 3 is the axial height of the lowest lifting area 33. Subsequently, as the compensator 3 rotates, the maximum length of the joint between the compensator 3 and the nut 1 is the axial lifting height of the highest lifting area 33.

[0114] For example, during the rotation of the compensator 3, the corresponding height difference areas can fit precisely and tightly. In order to facilitate the rotation of the compensator 3 to different height difference areas, an inclined transition surface 34 is provided at the connection point of adjacent lifting areas 33 from low to high, so that different lifting areas 33 can transition smoothly and avoid jamming.

[0115] For example, no inclined transition surface 34 is provided between the highest lifting area 33 and the lowest lifting area 33. When the nut 1 and the compensator 3 are connected in the initial position, the highest lifting area 33 of the compensator 3 and the highest lifting area 33 of the nut 1 form a stop surface 35 in the screwing direction of the nut 1. That is, when the nut 1 is screwing in, the compensator 3 is driven to rotate with the nut 1 through the stop surface 35 between the nut 1 and the compensator 3. When the nut 1 can no longer rotate, the compensator 3 continues to rotate in the screwing direction of the nut 1 to make the compensator 3 lift to compensate for the displacement, so that the nut 1 and the screw 2 are locked.

[0116] For example, the aforementioned lifting zone 33 can also be configured to increase continuously and gradually, meaning the height of the lifting zone 33 changes smoothly and continuously along the circumference, forming a spiraling upward slope. No inclined transition surface is needed between adjacent lifting zones 33, thus achieving a stepless transition, a smoother rotation process, and no jamming. The axial displacement of the compensator 3 changes continuously during rotation, enabling stepless adjustment. Furthermore, to ensure that the compensator 3 can be locked at any position within the lifting zone 33, an auxiliary locking structure can be used to fix the position of the compensator 3 relative to the lifting zone 33.

[0117] For example, the above-mentioned auxiliary locking structure can have a threaded hole drilled radially through the outer periphery of the compensator 3. By setting a set screw in the threaded hole, when the compensator 3 is rotated to the desired position, the set screw is tightened so that the end of the set screw abuts against the surface of the screw 2, thereby locking the relative rotation between the compensator 3 and the nut 1.

[0118] Optionally, in embodiments of this application, the total lifting stroke of the lifting area 33 of the inner ring 31 and the outer ring 32 is equal, and is greater than or equal to the axial lifting height of a single second threaded unit or a single first threaded unit.

[0119] For example, in this embodiment, there are 5 lifting zones between the nut 1 and the compensator. The total compensation stroke of the 5 lifting zones is greater than or equal to the axial stroke of the nut 1 between two adjacent second thread units (one thread unit). For example, if the unit axial stroke of one thread unit is 1 mm, then the compensation stroke of each segment of the compensation structure (the axial height of each lifting zone) is greater than or equal to 0.2 mm.

[0120] For example, the compensation structure on the compensator 3 and the nut 1 can also be set as a single-layer ring structure. The end faces of the compensator 3 and the nut 1 are set as a matching structure, and the end faces of the two are divided into the same number of lifting areas 33. It is only necessary to connect the lifting area 33 on the compensator 3 with the lifting area 33 on the nut 1 to ensure that the height of each connected lifting area 33 is the same.

[0121] For example, to ensure the stability of the single-layer ring, a guide sleeve can be fitted onto the top of the outer periphery of the nut 1. The bottom of the guide sleeve is fixedly connected to the nut 1, and the top of the guide sleeve is fitted onto the outer periphery of the compensator 3. The inner wall of the guide sleeve fits against the outer wall of the compensator 3, allowing the compensator 3 to rotate along the guide sleeve and also guiding the guide sleeve to move axially upwards. It should be noted that the guide sleeve is positioned near the top of the nut 1, so that it does not affect the disassembly of the nut 1. At the same time, it also avoids the guide sleeve completely covering the compensator 3. After the nut 1 is screwed into place, the compensator 3 can still be adjusted. The guide sleeve only needs to provide a certain sliding guiding function for the compensator 3.

[0122] For example, the compensator 3 can also be configured as an elastic compensator 3, including an elastic deformation part and a rigid support part; specifically, the elastic deformation part can be configured as a wave spring, a disc spring, or an elastic rubber body. During the process of screwing the nut 1 into the pre-tightened state, the elastic compensator 3 is compressed and stores elastic potential energy. When the nut 1 reaches the pre-tightened position, the elastic compensator 3 releases the elastic potential energy and generates an elastic recovery displacement along the axial direction of the screw 2, pushing the nut 1 to form a locking fit with the groove structure 5. In this embodiment, axial displacement is not achieved by rotating the compensator 3, but by using the compression and recovery of the elastic element to achieve automatic compensation, which makes the operation simpler and is suitable for scenarios with high requirements for ease of operation.

[0123] Optionally, in embodiments of this application, such as Figures 2-4 As shown, in the inner ring 31 and the outer ring 32, the lifting area 33 with the same axial height is offset by 180° in the circumferential direction of the compensator 3 and the nut 1.

[0124] For example, the lifting areas 33 of the inner ring 31 and the outer ring 32 are set with the same axial height offset by 180°.

[0125] It should be noted that for the axial height setting of the lifting zone, if higher precision is required, the lifting zone 33 of the compensator 3 can be divided into more equal numbers. For example, when the unit axial travel of a thread unit is 1.2mm and the precision of a single lifting zone is 0.2mm, the lifting zone can be divided into 6 sections.

[0126] This application also provides a fastening device, which is provided with the aforementioned self-locking bolt.

[0127] In the above embodiments of this application, the screwing of the nut 1 of this bolt relies on the "gradual lifting" of each thread unit to achieve the accumulation of axial displacement. This can easily lead to a key problem in engineering practice: the precise axial stroke required to achieve the ideal fastening state is almost impossible to be exactly equal to an integer multiple of the axial stroke of a single thread unit.

[0128] To address the aforementioned problems, this invention creatively introduces a stroke compensator 3 component.

[0129] The compensator 3 is located between the nut 1 and the workpiece 11 to be fastened. The compensator 3 is in close contact with the inner end face of the nut 1 (the end face near the workpiece 11 to be fastened). Its outer contour matches the nut 1, and its inner hole is slightly larger than the outer diameter of the thread and is smooth without threads.

[0130] The contact surface between the compensator 3 and the nut 1 is designed as two concentric annular regions, and each annular region is evenly divided into multiple circumferentially distributed lifting areas 33.

[0131] The surfaces of the aforementioned multiple raised zones 33 have a predetermined height difference. Within the same layer, the height difference between adjacent raised zones 33 is the same, and the surface height increases sequentially along the circumferential direction, forming a "step".

[0132] The total lifting stroke of all lifting zones 33 in both the inner and outer layers is equal, and this total stroke must be greater than or equal to the axial height difference of a single thread unit in the threaded pair.

[0133] The inner and outer layers have lifting zones 33 of the same height, positioned opposite each other about the center of the circular hole to ensure balanced force distribution. A slight ramp 34 serves as an inclined transition surface between adjacent lifting zones 33, facilitating smooth lifting during rotation.

[0134] The working principle of the above-mentioned fastening device is explained below:

[0135] The contact surface of the nut 1 has the same lifting area 33 as the compensator 3. In the initial state (before the nut 1 and the compensator 3 are screwed in), the lifting areas 33 of the two are engaged with each other. When the nut 1 is tightened, the compensator 3 rotates accordingly. At this time, the compensator 3 does not perform the compensation function.

[0136] When nut 1 and compensator 3 are screwed to the tightening critical point, and the required pre-tightening position is exactly between the strokes of two thread units, nut 1 cannot continue to tighten and lift because the thread structure 6 is stuck by the "peak" of the groove structure 5 of screw 2. The peak of the groove structure 5 is the highest point of the second convex section 102.

[0137] At this point, keep nut 1 stationary and begin rotating compensator 3 independently. As compensator 3 rotates, the corresponding lifting area that contacts nut 1 experiences relative lifting due to the change in elevation, thereby pushing nut 1 (relative to the workpiece) to produce a small, precise additional axial displacement.

[0138] Complete the tightening: By rotating the compensator 3 to select the appropriate height of the lifting zone 33 for alignment, the required tightening stroke and pre-tightening force can be accurately achieved to complete the final tightening.

[0139] After tightening, the anti-loosening performance of the entire bolt connection system is guaranteed by a dual mechanism:

[0140] The threaded pair itself: By combining the "bearing structure 12 that provides a force opposite to the preload to the nut 1 with the self-locking structure 13 that limits the rotation of the nut 1 on both sides of the bearing structure 12", the "wedge effect" that causes directional loosening is eliminated.

[0141] The lifting area interface between the nut and the compensator: This contact surface is composed of multiple planar lifting areas 33 perpendicular to the axial direction of the screw 2. Even in the event of extreme impact, the possible minute random rotational effects will not be converted into rotational accumulation because the contact surface between the nut 1 and the compensator 3 is planar; furthermore, due to the symmetry and randomness of the lifting area 33 structure, the probability of the aforementioned minute random rotational effects is equal in the circumferential direction, and they will not accumulate continuously in a single direction, thus avoiding irreversible loosening.

[0142] The beneficial effects of this application are as follows:

[0143] (1) Fundamental anti-loosening: The "wedge effect" is eliminated from the thread geometry, and the anti-loosening principle is superior to all existing "patchwork" technologies.

[0144] (2) High reliability: Combined with the self-locking of the threaded pair and the anti-loosening of the compensator plane, the performance is extremely reliable under severe vibration and impact.

[0145] (3) Reusable: All parts are mechanical structures and will not be damaged after disassembly, and can be reused multiple times; Precise pre-tightening: The original stroke compensator solves the problem of precise pre-tightening of discrete thread units and realizes the feasibility of engineering applications.

[0146] (4) Relatively simple structure: Compared with complex mechanical anti-loosening schemes, the core structure of this invention is still a bolt-nut-compensator system, which is easy to produce and install.

[0147] It should be noted that the bolt anti-loosening solution provided by this invention is groundbreaking in both principle and practice, and is particularly applicable to, but not limited to, fields with extremely high requirements for connection reliability, such as aerospace, rail transportation, heavy machinery, and energy equipment.

[0148] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A self-locking bolt, characterized in that, include: Nuts, screws, and compensators; The nut is provided with an internal thread, and the screw is provided with an external thread that matches the internal thread; The internal thread and the external thread include mutually matching thread units. The thread units at the matching positions of the internal thread and the external thread are different. The thread unit includes multiple first thread units and multiple second thread units. Each second thread unit includes a thread groove. The thread groove includes a slot structure with axial height. The first thread unit includes a thread structure adapted to the slot structure. When the thread structure is screwed into the pre-tightened state along the thread groove, a bearing structure is formed between the slot structure and the thread structure. The bearing structure provides a force to the nut that is opposite to the pre-tightening force. Furthermore, the slot structure and the thread structure form a self-locking structure through the mating surface in the screwing direction of the nut. The compensator is disposed between the nut and the workpiece to be fastened, and when the nut and the compensator are screwed into a preset position, the compensator generates an axial displacement in a predetermined direction. At the preset position, the gap between the compensator and the workpiece to be fastened is less than the axial lifting height of the thread structure between two adjacent slot structures. The preset direction is the rotation direction away from the nut, and the axial displacement is not less than the stroke required for the slot structure and the thread structure to reach the pre-tightened state.

2. The self-locking bolt according to claim 1, characterized in that, The groove structure includes a first fixing part, and the thread structure includes a second fixing part; When the threaded structure is screwed into the pre-tightened state along the thread groove, the first fixing part and the second fixing part constitute the bearing structure and the self-locking structure within a predetermined fitting range, and the first fixing part engages with the second fixing part in the screwing direction of the nut.

3. The self-locking bolt according to claim 2, characterized in that, The groove structure further includes a first force-bearing part, and the thread structure further includes a second force-bearing part; When the threaded structure is screwed into the pre-tightened state along the thread groove, the first force-bearing part and the second force-bearing part constitute the bearing structure within a predetermined contact range, and the first fixing part and the second fixing part constitute the self-locking structure within a predetermined contact range, and the first force-bearing part and the second force-bearing part are locked in the screwing direction of the nut.

4. The self-locking bolt according to claim 3, characterized in that, The first threaded unit includes a first upper thread and a first lower thread, and the second threaded unit includes a second upper thread and a second lower thread; The first and second upper thread lines are line segments arranged parallel to the screwing direction, which are used to provide screwing guidance for the nut; The second lower thread includes a second horizontal bearing section and a first convex section and a second convex section disposed at both ends of the second horizontal bearing section. The second convex section is disposed along the screwing direction of the nut and forms a preset angle with the second lower thread. Along the screwing direction of the nut, the axial height of the second convex section is greater than the axial height of the first convex section. The first lower thread and the second lower thread are configured to cooperate. The line connecting the top of the first protrusion and the top of the second protrusion is set parallel to the second upper thread line; The threaded groove is formed between the second upper thread and the second lower thread of each second threaded unit. The second horizontal bearing section serves as the first force-bearing part, and the first convex section and the second convex section serve as the first fixing part. The second horizontal bearing section cooperates with the first lower thread to form the bearing structure. The first convex section and the second convex section cooperate with the first lower thread to form the mating surface. The thread structure is formed between the first upper thread and the first lower thread of each first thread unit, and the minimum axial width of the thread groove is greater than the maximum axial width of the thread structure.

5. The self-locking bolt according to claim 4, characterized in that, The angle between the first upper thread and the horizontal plane, and the angle between the second upper thread and the horizontal plane, are both equal to the thread helix angle of the self-locking bolt.

6. The self-locking bolt according to claim 4, characterized in that, The included angle between the first convex segment and the second convex segment between two adjacent second threaded units is 15°~180°.

7. The self-locking bolt according to claim 1, characterized in that, The compensator is sleeved on the screw and rotates relative to the screw. Compensation structures are provided on the end faces of the compensator and the nut that are close to each other. The compensation structures compensate for the axial displacement of the nut after the nut reaches the pre-tightened state.

8. The self-locking bolt according to claim 7, characterized in that, The compensation structure includes a first compensation structure disposed on the end face of the nut near the compensator and a second compensation structure disposed on the end face of the compensator near the nut. Both the first compensation structure and the second compensation structure are double-ring structures, including an inner ring and an outer ring. The inner diameter of the inner ring is larger than the major diameter of the screw, and the shape of the outer ring is adapted to the shape of the nut. Lifting structures for lifting the compensator are provided on the end faces of the inner ring and the outer ring, so that the compensator can be displaced axially on the screw.

9. The self-locking bolt according to claim 8, characterized in that, The lifting structure includes multiple lifting zones perpendicular to the screw axis; Both the inner and outer rings are provided with lifting zones that are distributed circumferentially and whose height increases in a stepped manner. Adjacent lifting zones are connected by an inclined transition surface to guide the compensator to move relative to each other in the lifting direction. No inclined transition surface is provided between the highest and lowest lifting zones, thus forming a stop surface to prevent the compensator from moving relative to each other in the opposite direction.

10. The self-locking bolt according to claim 9, characterized in that, The total lifting stroke of the inner ring and the outer ring is equal, and is greater than or equal to the axial lifting height of a single second threaded unit or a single first threaded unit.

11. The self-locking bolt according to claim 10, characterized in that, In the inner ring and the outer ring, the lifting areas with the same axial height are offset by 180° in the circumferential direction of the compensator and the nut.

12. The self-locking bolt according to claim 11, characterized in that, The number of lifting zones of the compensator is set according to the required compensation accuracy of the nut.

13. A fastening device, characterized in that, The fastening device is provided with a self-locking bolt according to any one of claims 1 to 12.

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