A double thread locking anti-loose connector plug

Abstract

The application discloses a double-thread locking anti-loosening connector plug and belongs to the technical field of electric connectors. The connector plug comprises a plug shell, a plug tail and a terminal inner core. The end of the plug shell is provided with a first threaded part, the end of the plug tail is provided with a second threaded part, and the two are connected through thread locking. The outer thread of the terminal inner core is matched with the inner thread at the front end of the plug tail to form an inner-outer double-thread locking structure, and the rotation directions of the two threads are the same. The first threaded part and the second threaded part are in interference fit, and the friction torque between the two is greater than that between the inner threads, so that the locking force of the outer thread plays a leading role in the double locking. During assembly, the inner thread at the front end is first engaged to establish a sealing compression force, and then the outer thread is intervened to lock the compression state. The application realizes the technical effect that the thread loosening and the sealing failure are separated, can maintain sealing reliability in a strong vibration environment, has a simple structure, is easy to assemble and is suitable for batch production.

Description

Technical Field

[0001] This invention relates to the field of electrical connector technology, specifically to a double-threaded locking connector plug for use in high-vibration scenarios such as stage lighting, outdoor industry, and automotive applications to prevent loosening. Background Technology

[0002] Existing connector plugs have external threads on the outer wall of the terminal core and corresponding internal threads on the inner wall of the front end of the plug tail. The terminal core and the plug tail are connected by this threaded engagement. However, the plug shell only serves as an outer protective sleeve fitted over the terminal core, and there is no direct threaded engagement between the plug shell and the plug tail. Under prolonged use or in environments with strong vibration, this threaded connection is prone to gradually loosening due to reverse rotation, causing relative displacement between the plug tail and the terminal core, and in severe cases, detachment.

[0003] More importantly, connector plugs typically have a sealing ring at the front end of the external thread of the terminal core. When the plug tail is tightened, the front end of the plug tail interferes with and is compressed against the sealing ring, forming a closed space inside the plug tail, thus achieving a waterproof seal. The sealing effect of this closed space depends on the tightness of the thread between the plug tail and the terminal core. When the threaded connection at this point loosens, the axial gap between the plug tail and the terminal core increases, the clamping force decreases or disappears, the sealing ring is not compressed enough, the sealing performance of the closed space is compromised, leading to seal failure. External moisture, dust, etc., can then enter the plug, causing serious safety hazards such as short circuits and corrosion.

[0004] Therefore, the existing connector plug's anti-loosening structure between the plug tail and the terminal core cannot simultaneously meet the usage requirements of connection reliability, vibration resistance and anti-loosening, and sealing reliability. Summary of the Invention

[0005] This invention addresses the problem that in existing connector plugs, the connection between the plug tail and the terminal core is prone to loosening, and loose threads can lead to sealing failure and water ingress risks. It provides a connector plug with double thread locking to prevent loosening.

[0006] This invention achieves double-threaded locking by using an internal thread at the front end of the plug tail to engage with the external thread of the terminal core, and a threaded engagement between the end of the plug housing and the end of the plug tail. Specifically, the internal thread at the front end of the plug tail securely connects the terminal core to the plug tail, while the threaded engagement between the ends of the plug housing and the plug tail securely connects the plug tail to the plug housing. After assembly, the plug housing, plug tail, and terminal core form a rigid whole through the double-threaded connection. Compared to traditional structures that rely solely on the external thread of the terminal core and the internal thread at the front end of the plug tail for load-bearing, this invention uses both internal and external threads to share the load. Even if one threaded connection becomes slightly loose under extreme vibration, the other threaded connection can still maintain the clamping force between the plug tail and the terminal core, thus ensuring the compression of the sealing ring, maintaining the integrity of the enclosed space, and preventing seal failure and water ingress.

[0007] The terminal core is inserted into the plug housing from the front end. The plug housing has a positioning step and a positioning notch inside. The positioning step is used to axially limit the insertion stroke of the terminal core, and the positioning notch is used to circumferentially position the terminal core, ensuring that the external thread of the terminal core is accurately aligned with the internal thread at the front end of the plug tail after the terminal core is assembled.

[0008] It should be noted that, in this invention, the threaded engagement between the end of the plug housing and the end of the plug tail is not limited to the form of "the first threaded portion at the end of the plug housing is an internal thread and the second threaded portion at the end of the plug tail is an external thread". In other embodiments, the first threaded portion at the end of the plug housing may also be an external thread, and the second threaded portion at the end of the plug tail may be an internal thread; that is, the end of the plug housing and the end of the plug tail are respectively provided with mutually engaging first and second threaded portions. Whether the first and second threaded portions are specifically internal or external threads—that is, the end of the plug housing is an internal thread and the end of the plug tail is an external thread, or the end of the plug housing is an external thread and the end of the plug tail is an internal thread—all fall within the protection scope of this invention. The following description only uses "the first threaded portion at the end of the plug housing is an internal thread and the second threaded portion at the end of the plug tail is an external thread" as a preferred embodiment, but the protection scope of this invention is not limited thereto.

[0009] Furthermore, the threaded fit between the end of the plug housing and the end of the plug tail can be achieved using an interference fit, such as by increasing the thread width, increasing the thread height, setting a pitch difference, or misaligning the thread starting phase, to further increase the frictional torque between the threaded pairs and effectively enhance vibration resistance and anti-loosening performance. The overall structure is simplified, with a high degree of one-piece molding, eliminating the need for additional limiting accessories such as snap rings, simplifying assembly, reducing production costs, and ensuring high safety in use.

[0010] The technical solution of the present invention is as follows:

[0011] A connector plug with double threaded locking to prevent loosening includes a plug housing, a plug tail, and a terminal core;

[0012] The plug housing has a cylindrical structure, with a front end and an end end;

[0013] The plug tail section has a cylindrical structure, with a front end and an end end, and the inner wall of the front end of the plug tail section is provided with internal threads.

[0014] The end of the plug housing and the end of the plug tail are respectively provided with mating internal threads and external threads, which are locked together by the threaded engagement to fix the plug tail to the plug housing;

[0015] The outer wall of the terminal core is provided with an external thread, and the external thread of the terminal core cooperates with the internal thread at the front end of the plug tail to realize the threaded locking connection between the terminal core and the plug tail.

[0016] The internal thread at the front end of the plug has the same direction of rotation as the thread at its end that mates with the plug housing.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. Double locking for reliable connection: Independent threaded locking fits are formed between the plug shell and the plug tail, and between the plug tail and the terminal core. The double threads share the load, effectively improving connection strength and vibration resistance.

[0019] 2. Interference fit, excellent anti-loosening performance: The threaded fit between the end of the plug shell and the end of the plug tail adopts an interference fit, which significantly increases the frictional torque between the threaded pairs and effectively prevents the threads from loosening due to vibration.

[0020] 3. Reliable sealing and excellent waterproof performance: A sealing ring is provided at the front end of the external thread of the terminal core. When the plug tail is tightened with the terminal core, the front end of the plug tail interferes with and is squeezed against the sealing ring, forming a closed space inside the plug tail. The double-threaded locking structure ensures stable and reliable clamping force between the plug tail and the terminal core. Even if one threaded connection becomes slightly loose under extreme vibration, the other threaded connection can still maintain the clamping force required for sealing, effectively preventing seal failure and water ingress risks due to loose connection.

[0021] 4. Good overall rigidity and stable structure: The plug shell, plug tail and terminal core are connected by double threads to form a rigid whole. The inner and outer threads jointly constrain the relative movement between the components, and the overall structural stability is significantly better than the traditional single thread structure.

[0022] 5. Simplified structure and easy assembly: All threaded structures, positioning steps, and positioning notches are integrally molded on each component, eliminating the need for additional accessories such as snap rings, springs, and steel balls; each component can be assembled by rotating the threads, with consistent rotation direction and uniform assembly direction, requiring no special tools, resulting in low production costs and suitability for automated mass production.

[0023] 6. Unexpected Technical Effects: The double-threaded locking structure of this invention produces unexpected technical effects. In traditional structures, once the threads loosen, the sealing ring clamping force is immediately lost, and there is an inevitable causal relationship between sealing failure and thread loosening. However, in this invention, even if the internal thread loosens slightly under extreme vibration conditions, the interference fit of the external thread can still firmly lock the plug tail to the plug housing, forcing the front end of the plug tail to continuously press against the sealing ring, thus maintaining sealing performance even in the event of thread failure. This technical effect of "separating thread loosening from sealing failure" is something that those skilled in the art cannot foresee or deduce based on the anti-loosening design of traditional structures. At the same time, the frictional torque generated by the interference fit between the first threaded part at the end of the plug housing and the second threaded part at the end of the plug tail is greater than the frictional torque between the external thread on the outer wall of the terminal core and the internal thread on the inner wall of the front end of the plug tail, making the external thread locking force dominate in the double locking, further ensuring the stability of the sealing ring clamping force. The above synergistic effect has not been disclosed in the prior art. Attached Figure Description

[0024] Figure 1 This is an exploded view of the overall structure of the present invention, showing the disassembled state of the plug shell, plug tail, and terminal core;

[0025] Figure 2 This is a schematic diagram of the plug tail structure of the present invention, showing the distribution of the internal thread at the front end and the second thread at the end of the plug tail;

[0026] Figure 3 This is a schematic diagram of the plug housing structure of the present invention, showing the distribution of the first threaded portion at the end of the plug housing and the internal positioning steps and positioning notches;

[0027] Figure 4 This is a schematic diagram of the inner core structure of the terminal of the present invention, showing the distribution of the outer thread, positioning protrusion and sealing ring on the outer wall of the inner core of the terminal;

[0028] Figure 5 This is a schematic cross-sectional view of the overall structure of the present invention after assembly, showing the threaded locking fit and enclosed space of the plug shell, plug tail, and terminal core.

[0029] Figure 6This is a partially enlarged schematic diagram showing the interference fit between the first threaded portion at the end of the plug housing and the second threaded portion at the end of the plug tail of the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1-Plug housing;

[0032] 11-The front end of the plug housing;

[0033] 12 - The end of the plug housing;

[0034] 13 - The first threaded portion at the end of the plug housing;

[0035] 14- Positioning steps inside the plug housing;

[0036] 15 - Positioning notch inside the plug housing;

[0037] 2-Plug tail;

[0038] 21 - The front end of the plug tail;

[0039] 22 - The end of the plug tail;

[0040] 23 - The second threaded portion at the end of the plug tail;

[0041] 24 - Internal threads on the inner wall of the front end of the plug tail;

[0042] 25 - Limiting step at the end of the plug;

[0043] 3-Terminal inner core;

[0044] 31 - External threads on the outer wall of the terminal core;

[0045] Positioning protrusions on the inner core of the 32-terminal;

[0046] 33 - Positioning guide surface of the terminal core;

[0047] 34-The sealing ring at the front end of the inner core external thread of the terminal. Detailed Implementation

[0048] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0049] It should be noted that the core improvement of this invention lies in the double-threaded locking structure between the plug shell, the plug tail, and the terminal core, as well as the limiting assembly structure of the terminal core within the plug shell via positioning steps and positioning notches. As for the electrical connection parts in the terminal core used for transmitting electrical signals (such as the specific arrangement of conductive terminals), the tail nut at the end of the plug for connecting the cable and its matching nut sealing ring, and the specific structure of the unlocking button on the plug shell, these are all well-known prior art in the field, and their specific implementations do not involve the improvement points of this invention; therefore, they will not be described in detail here. Those skilled in the art can fully implement the technical solution of this invention based on the double-threaded locking structure disclosed in this invention, combined with common knowledge in the field.

[0050] Overall Structure

[0051] like Figures 1 to 5 As shown, the present invention provides a connector plug with double thread locking to prevent loosening, which mainly includes a plug shell (1), a plug tail (2) and a terminal core (3).

[0052] The plug housing (1) has a cylindrical structure with a front end (11) and an end end (12). The end end (12) of the plug housing (1) is provided with a first threaded portion (13). The interior of the plug housing (1) is provided with a positioning step (14) and a positioning notch (15). The positioning step (14) is used to axially limit the insertion stroke of the terminal core (3), and the positioning notch (15) is used to circumferentially position the terminal core (3).

[0053] The plug tail (2) has a cylindrical structure with a front end (21) and an end end (22). The inner wall of the front end (21) of the plug tail (2) is provided with an internal thread (24) for engaging with the external thread (31) of the terminal core (3). The end end (22) of the plug tail (2) is provided with a second thread (23) for engaging with the first thread (13) of the plug housing (1). The front end (21) and the end end (22) are integrally formed. The plug tail (2) is provided with a limiting step (25) for abutting against the end face (12) of the plug housing (1) to limit the assembly depth of the plug tail (2) within the plug housing (1).

[0054] The terminal core (3) has a columnar structure and is inserted into the plug housing (1) from the front end (11). The outer wall of the terminal core (3) is provided with a positioning protrusion (32) that matches the shape of the positioning notch (15). When the terminal core (3) is inserted, axial positioning is achieved by the positioning step (14), and circumferential positioning is achieved by the positioning protrusion (32) embedding into the positioning notch (15), ensuring that the external thread (31) of the terminal core (3) is accurately aligned with the internal thread (24) of the inner wall of the front end of the plug tail (2) after the terminal core (3) is assembled. The outer wall of the terminal core (3) is provided with an external thread (31) for mating with the internal thread (24) of the plug tail (2). A sealing ring (34) is provided at the front end of the external thread (31) of the terminal core (3).

[0055] It should be noted that the above description of "the first threaded portion (13) of the end (12) of the plug housing (1) being an internal thread and the second threaded portion (23) of the end (22) of the plug tail (2) being an external thread" is only a preferred embodiment of the present invention and is not a limitation on the scope of protection of the present invention. In other embodiments, the first threaded portion (13) of the end (12) of the plug housing (1) may also be an external thread, and the second threaded portion (23) of the end (22) of the plug tail (2) may be an internal thread, and the two may also achieve a locking connection through threaded engagement. That is, the end (12) of the plug housing (1) and the end (22) of the plug tail (2) are respectively provided with a first threaded portion (13) and a second threaded portion (23) that engage with each other. Whether the first threaded portion (13) and the second threaded portion (23) are specifically internal or external threads is within the scope of protection of the present invention. Based on the above disclosure of the present invention, those skilled in the art can interchange the positions of the internal and external threads without creative effort, and such embodiments should be covered within the scope of protection of the present invention.

[0056] Threaded locking structure

[0057] In this invention, the plug housing (1) and the plug tail (2) are locked together by threaded engagement. The engagement sequence of the two threads can vary depending on the setting of the thread starting position, and two implementation methods are described below.

[0058] Conventional implementation method

[0059] The internal thread (24) on the inner wall of the front end of the plug tail (2) and the second thread (23) at the end of the plug tail (2) are designed to be compatible in terms of thread start phase and axial position. When the plug tail (2) is screwed into the end (12) of the plug housing (1), the internal thread (24) on the inner wall of the front end of the plug tail (2) and the external thread (31) on the outer wall of the terminal core (3), as well as the second thread (23) at the end of the plug tail (2) and the first thread (13) at the end of the plug housing (1), enter the meshing state simultaneously and lock simultaneously. The plug tail (2) is rotated continuously until the limiting step (25) of the plug tail (2) abuts against the end face of the end (12) of the plug housing (1), thus achieving the assembly in place. After the assembly is in place, the front end (21) of the plug tail (2) interferes and is squeezed with the sealing ring (34), forming a closed space inside the plug tail (2) to achieve waterproof sealing.

[0060] Preferred Implementation

[0061] As a further preferred embodiment of the present invention, the axial position of the internal thread (24) on the inner wall of the front end of the plug tail (2) relative to the second thread (23) at the end of the plug tail (2) can be adjusted so that the internal thread (24) on the inner wall of the front end of the plug tail (2) is axially positioned in front of the second thread (23) at its end, so that the two threads enter the meshing state in the following order during assembly:

[0062] Screw the plug tail (2) into the end (12) of the plug housing (1). In the initial stage of screwing in, the internal thread (24) on the inner wall of the front end of the plug tail (2) first engages with the external thread (31) on the outer wall of the terminal core (3), and begins to generate axial tension. The front end (21) of the plug tail (2) gradually moves towards the sealing ring (34) and approaches the sealing ring (34). At this time, the front end (21) of the plug tail (2) has not yet contacted the sealing ring (34), and the sealing ring (34) has not undergone compression deformation.

[0063] As the plug tail (2) continues to screw in, the second thread (23) at the end of the plug tail (2) begins to engage with the first thread (13) at the end of the plug housing (1). Thereafter, the two threads are simultaneously stressed and screwed in—the internal thread (24) on the inner wall of the front end of the plug tail (2) and the external thread (31) on the outer wall of the terminal core (3) continue to provide axial tension, and the second thread (23) at the end of the plug tail (2) and the first thread (13) at the end of the plug housing (1) simultaneously provide locking force to fix the plug tail (2) to the plug housing (1).

[0064] As the assembly nears completion, the front end (21) of the plug tail (2) begins to contact and compress the sealing ring (34), causing the sealing ring (34) to undergo compression deformation. The two threads work together to continuously rotate the plug tail (2) until the limiting step (25) of the plug tail (2) abuts against the end face (12) of the plug housing (1). At this time, the two threads are simultaneously assembled into place, the sealing ring (34) is compressed to the design value, and the closed space is fully established.

[0065] The assembly sequence of this preferred embodiment has key mechanical significance: the internal thread (24) on the inner wall of the front end of the plug tail (2) first establishes an initial axial tension with the external thread (31) on the outer wall of the terminal core (3), causing the front end (21) of the plug tail (2) to gradually move towards the sealing ring (34), eliminating the axial gap between the plug tail (2) and the terminal core (3); the second thread (23) at the end of the plug tail (2) then engages with the first thread (13) at the end of the plug housing (1) and works together to fix the plug tail (2) firmly to the plug housing (1); in the final stage of assembly, the front end (21) of the plug tail (2) contacts and compresses the sealing ring (34), and the two threads work together to maintain this compression state, thereby locking the compression state of the sealing ring (34). The two threads engage one after the other during the same screwing process and work together to complete the structural locking and sealing.

[0066] It is particularly important to emphasize that if the second thread (23) at the end of the plug tail (2) and the first thread (13) at the end of the plug housing (1) engage and lock in place before the internal thread (24) on the inner wall of the front end of the plug tail (2) and the external thread (31) on the outer wall of the terminal core (3), the axial position of the plug tail (2) will be fixed in advance by the second thread (23) and the first thread (13). The internal thread (24) on the inner wall of the front end of the plug tail (2) will not be able to continue to tighten to fully eliminate the axial gap. The front end (21) of the plug tail (2) will not be able to move to the position of contact with the sealing ring (34). The sealing ring (34) will not be compressed. The axial gap between the plug tail (2) and the terminal core (3) will not be eliminated. The terminal core (3) will be in an axial floating state. In a vibration environment, it is easy to generate relative displacement and impact, which will accelerate the wear of the threads. At the same time, insufficient compression of the sealing ring (34) will directly lead to sealing failure, causing safety hazards such as water ingress and short circuit. The present invention effectively eliminates this risk by designing the internal thread to engage first and the external thread to engage later, ensuring that the clamping force of the sealing ring (34) is fully established and locked during the assembly stage.

[0067] In this invention, the internal thread (24) on the inner wall of the front end of the plug tail (2) has the same rotation direction as the second thread (23) at the end of the plug tail (2). That is, if the second thread (23) is a right-hand thread, then the internal thread (24) is also a right-hand thread; if the second thread (23) is a left-hand thread, then the internal thread (24) is also a left-hand thread. The two threads have the same rotation direction, so that the two threads have the same rotation direction during the screwing-in process of the plug tail (2), the assembly direction is unified, and the operation is simple and efficient.

[0068] Interference mating structure

[0069] like Figure 6 As shown, as a further improvement of the present invention, the threaded fit between the first threaded portion (13) at the end (12) of the plug housing (1) and the second threaded portion (23) at the end (22) of the plug tail (2) is an interference fit. This interference fit can be achieved in various ways:

[0070] Method 1: The tooth width of the second thread (23) is greater than the tooth groove width of the first thread (13). When the plug tail (2) is screwed into the plug housing (1), an interference fit is formed between the thread of the second thread (23) and the tooth groove of the first thread (13). Alternatively, the interference fit can be achieved by making the tooth height of the second thread (23) greater than the tooth depth of the first thread (13).

[0071] Method 2: A small pitch difference is set between the second threaded part (23) and the first threaded part (13) to cause axial interference between the first threaded part (13) and the second threaded part (23) during the screwing process. Alternatively, by misaligning the starting phase of the threads of the first threaded part (13) and the second threaded part (23), circumferential interference is caused by the threads during the screwing process.

[0072] It should be noted that the interference amount of the above-mentioned interference fit should be reasonably selected according to the specific materials and dimensions of the plug housing (1) and the plug tail (2), so as to generate sufficient frictional torque to achieve vibration resistance and anti-loosening, without causing jamming or excessive deformation during assembly. Generally speaking, the interference amount only needs to generate a slight radial or axial positive pressure between the threaded pairs to significantly increase the frictional torque, and there is no need to set an excessively large interference amount. Based on the content disclosed in this invention, combined with the specific material characteristics and thread specifications, those skilled in the art can determine the appropriate interference range through a limited number of tests without any creative effort.

[0073] All of the above methods can generate additional radial or axial positive pressure between the threaded pairs, significantly increasing the frictional torque when the threaded pairs rotate, thereby effectively preventing thread loosening caused by vibration. It should be noted that, regardless of which method is used, as long as the first threaded part (13) and the second threaded part (23) form an interference fit when screwed together, they are all within the protection scope of this invention.

[0074] Meanwhile, due to the presence of interference fit, the connection between the plug tail (2) and the plug shell (1) is more stable, further ensuring the clamping force between the plug tail (2) and the terminal core (3) and ensuring the integrity of the enclosed space.

[0075] Assembly process

[0076] The assembly process of this invention is as follows:

[0077] First, insert the terminal core (3) into the plug housing (1) from the front end (11) of the plug housing (1). Axial positioning is achieved by positioning step (14), and circumferential positioning is achieved by positioning protrusion (32) embedded in positioning notch (15), ensuring that the external thread (31) of the terminal core (3) is in the correct position.

[0078] Then, screw the plug tail (2) into the end (12) of the plug housing (1). When the plug tail (2) is screwed in, the internal thread (24) of the front end (21) of the plug tail (2) first engages with the external thread (31) of the terminal core (3) and begins to tighten; as the plug tail (2) continues to be screwed in, the second thread (23) of the end (22) of the plug tail (2) then engages with the first thread (13) of the end (12) of the plug housing (1), and thereafter the two threads work together to lock together. Continue to rotate the plug tail (2) until the limiting step (25) of the plug tail (2) abuts against the end face (12) of the plug housing (1), thus achieving the assembly in place.

[0079] After assembly, the front end (21) of the plug tail (2) interferes with and is squeezed by the sealing ring (34), forming a closed space inside the plug tail (2). This closed space achieves waterproof sealing through the compression deformation of the sealing ring (34).

[0080] Sealing reliability analysis

[0081] In this invention, the sealing effect of the enclosed space depends on the clamping force between the plug tail (2) and the terminal core (3), which is maintained by the threaded engagement between the internal thread (24) on the inner wall of the front end of the plug tail (2) and the external thread (31) on the outer wall of the terminal core (3).

[0082] In the traditional structure (only the outer thread of the terminal core and the inner thread of the plug tail are threaded together), if the thread at this point becomes loose due to vibration, the clamping force between the plug tail (2) and the terminal core (3) will decrease or disappear. The compression of the sealing ring (34) will be insufficient, and the sealing performance of the enclosed space will be damaged, which will directly lead to sealing failure. External moisture, dust and other substances will enter the plug, causing serious safety hazards such as short circuit and corrosion.

[0083] In this invention, the threaded engagement between the second threaded portion (23) at the end (22) of the plug tail (2) and the first threaded portion (13) at the end (12) of the plug housing (1), and the threaded engagement between the external thread (31) on the outer wall of the terminal inner core (3) and the internal thread (24) on the inner wall of the front end of the plug tail (2), form two independent threaded locking structures. The two threads together maintain the clamping force between the plug tail (2) and the terminal inner core (3). Even if one of the threaded connections becomes slightly loose under extreme vibration conditions, the other threaded connection can still maintain the clamping force required for the sealing ring (34), thereby effectively preventing the failure of the enclosed space and the risk of water ingress.

[0084] In addition, the interference fit between the first threaded part (13) at the end (12) of the plug housing (1) and the second threaded part (23) at the end (22) of the plug tail (2) provides additional frictional torque, further enhancing the anti-vibration and anti-loosening capabilities, making the connection between the plug housing (1) and the plug tail (2) more stable and reliable.

[0085] Overall stability analysis

[0086] Compared to traditional structures, the double-threaded locking structure of this invention has significant advantages in overall stability. The plug shell (1), plug tail (2), and terminal core (3) are connected by two threads to form a rigid whole. The first thread (13), the second thread (23), the internal thread (24), and the external thread (31) together constrain the axial and circumferential relative movement between the components. Under strong vibration conditions, this rigid whole can effectively resist multi-directional vibration excitation and will not produce relative displacement or loosening between components. At the same time, the presence of interference fit further enhances the vibration resistance of the threaded connection, so that the overall structure can remain stable under extreme working conditions.

[0087] Analysis of Unexpected Technical Effects

[0088] The double-threaded locking structure of the present invention produces unexpected technical effects. In traditional structures, once the threads loosen, the sealing ring clamping force is immediately lost, and there is an inevitable causal relationship between sealing failure and thread loosening. In the present invention, the two threads play different functional roles: the fit between the first threaded part at the end of the plug housing and the second threaded part at the end of the plug tail provides a strong locking force through interference, firmly fixing the plug tail (2) to the plug housing (1); the internal thread on the inner wall of the front end of the plug tail (2) and the external thread on the outer wall of the terminal core (3) are responsible for providing the axial clamping force required by the sealing ring (34). Since the two threads have the same direction of rotation and lock synchronously, even if the internal thread loosens slightly under extreme vibration environment, the interference fit of the external thread can still maintain the axial position of the plug tail (2) unchanged, thereby forcing the front end of the plug tail (2) to continuously press the sealing ring (34). This technical effect of "separation of thread loosening and sealing failure" is something that those skilled in the art cannot foresee or deduce based on the anti-loosening design of traditional structures.

[0089] Furthermore, by setting the interference fit between the first threaded portion (13) at the end (12) of the plug housing (1) and the second threaded portion (23) at the end (22) of the plug tail (2), the frictional torque generated is greater than the frictional torque between the external thread (31) on the outer wall of the terminal inner core (3) and the internal thread (24) on the inner wall of the front end of the plug tail (2), making the external thread locking force dominant in the double locking. Even if the internal thread tends to loosen due to vibration, the plug tail (2) cannot rotate relative to the plug housing (1) because the external thread has a greater frictional torque, and the loosening tendency of the internal thread is effectively suppressed, thereby further ensuring the stability of the sealing ring (34) clamping force. The above synergistic effect has not been disclosed in the prior art and has outstanding substantial features and significant progress.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the concept and principles of the present invention should be included within the protection scope of the present invention.

[0091] Same day application statement

[0092] It should be noted that the applicant filed two separate patent applications on the same day for all the technical solutions described in this application (including the double-threaded locking structure between the plug shell, the plug tail, and the terminal core, and their mating relationship). The descriptions and drawings of the two patent applications are completely identical. The applicant legally enjoys the dual benefits of rapid rights confirmation and long-term protection brought about by the dual-application strategy, and undertakes to handle matters of duplicate authorization in accordance with the relevant regulations of the State Intellectual Property Office in subsequent procedures.

Claims

1. A connector plug with double-threaded locking to prevent loosening, characterized in that, include: The plug housing has a cylindrical structure. The plug tail has a cylindrical structure with an internal thread at the front end; The inner core of the terminal has external threads on its outer wall; The end of the plug housing and the end of the plug tail are respectively provided with internal and external threads that cooperate with each other. The two are locked together by the threaded engagement to fix the plug tail to the plug housing. The external thread of the terminal core engages with the internal thread at the front end of the plug to achieve a threaded locking connection between the terminal core and the plug tail. The internal thread at the front end of the plug has the same direction of rotation as the thread at its end that mates with the plug housing.

2. The connector plug with double thread locking and anti-loosening as described in claim 1, characterized in that: The threaded fit between the end of the plug housing and the end of the plug tail is an interference fit.

3. The connector plug with double thread locking and anti-loosening as described in claim 2, characterized in that: The interference fit is achieved through any of the following methods: The thread width at the end of the plug tail that mates with the plug housing is greater than the groove width of the thread at the end of the plug housing that mates with the plug tail; or, The thread height at the end of the plug tail that mates with the plug housing is greater than the thread depth at the end of the plug housing that mates with the plug tail; or, There is a pitch difference between the thread at the end of the plug tail that mates with the plug housing and the thread at the end of the plug housing that mates with the plug tail; or, The thread at the end of the plug that mates with the plug housing is misaligned with the thread at the end of the plug housing that mates with the plug tail.

4. The connector plug with double thread locking and anti-loosening as described in claim 1, characterized in that: The internal thread at the front end of the plug and the thread at its end for mating with the plug housing are either right-hand threads or left-hand threads.

5. The connector plug with double thread locking and anti-loosening as described in claim 1, characterized in that: The terminal core is inserted into the plug housing from the front end of the plug housing. The plug housing has a positioning step and a positioning notch inside. The positioning step is used to axially limit the terminal core, and the positioning notch is used to circumferentially position the terminal core.

6. The connector plug with double thread locking and anti-loosening as described in claim 1, characterized in that: A sealing ring is provided at the front end of the external thread of the terminal core. When the plug tail is screwed tightly with the terminal core, the front end of the plug tail interferes and is squeezed with the sealing ring, forming a closed space inside the plug tail.

7. The connector plug with double thread locking and anti-loosening as described in claim 1, characterized in that: The plug tail is provided with a limiting step, which is used to abut against the end face of the plug housing to limit the assembly depth of the plug tail in the plug housing.

8. The connector plug with double thread locking and anti-loosening as described in claim 1, characterized in that: The inner core of the terminal is provided with a positioning guide surface, which is used to abut against the front end face of the tail of the plug to limit the assembly depth of the inner core of the terminal in the tail of the plug.

9. The connector plug with double thread locking and anti-loosening as described in claim 1, characterized in that: The internal thread at the front end of the plug tail is located axially in front of the second thread at its end. When the plug tail is screwed into the end of the plug housing, the internal thread at the front end engages before the second thread at the end.

10. The connector plug with double thread locking and anti-loosening according to claim 2, characterized in that: The frictional torque generated by the interference fit between the first threaded portion at the end of the plug housing and the second threaded portion at the end of the plug tail is greater than the frictional torque between the external thread on the outer wall of the terminal inner core and the internal thread on the inner wall of the front end of the plug tail.

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