A waterproof low-voltage cable connection assembly

Abstract

This invention discloses a waterproof low-voltage cable connection assembly, comprising: a base, electrical terminals, an insulating sleeve, and a plug. The base includes a receiving platform, a plurality of electrical connecting posts disposed on the contact surface of the receiving platform, and a plurality of conical connecting bosses disposed on the outer side of the receiving platform. The electrical terminals are mounted on the conical connecting bosses, and the insulating sleeve is sleeved on the outer side of the electrical terminals. The insulating sleeve forms an interference fit with the bottom of the connecting bosses, and the top of the insulating sleeve forms an interference fit through the plug. The side wall of the insulating sleeve has an outwardly extending sub-sleeve, which is used to accommodate the electrical connection end of the electrical terminal. The port of the sub-sleeve is a conical groove structure with gradually increasing wire diameter, used to form an interference fit with an external plug-in cable. The base is bolted to the mounting slot of the transformer housing, forming a sealed and waterproof structure for the electrical terminals and sleeve to fit together.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and more specifically to a waterproof low-voltage cable connection assembly. Background Technology

[0002] Transformers are one of the main pieces of equipment in the power grid architecture. As existing outdoor transformer equipment needs to be installed in different outdoor environments, in low-lying and flood-prone areas, there is a risk of moisture intrusion into the transformer tank. Since the existing transformer tanks are mainly connected to external cables by plug-in connection and locked and sealed with nuts and washers, there is a problem of insufficient sealing performance. Working in low-lying and humid environments for a long time poses a risk of moisture intrusion into the transformer tank. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a waterproof low-voltage cable connection assembly, which improves the waterproof performance of the low-voltage cable connection assembly by setting an insulating sleeve to fit onto the conical connection boss of the base and encapsulating the electrical terminals of the conical connection boss.

[0004] The present invention provides a waterproof low-voltage cable connection assembly, which includes: a base, electrical terminals, an insulating sleeve and a plug. The base includes a receiving platform, a plurality of electrical connection posts disposed on the contact surface of the receiving platform, and a plurality of conical connection bosses disposed on the outer side of the receiving platform. The electrical terminal is mounted on the tapered connecting boss, and the insulating sleeve is sleeved on the outside of the electrical terminal. The insulating sleeve forms an interference fit with the bottom of the connecting boss, and the top of the insulating sleeve forms an interference fit through a plug. The insulating sleeve has an outwardly extending sub-sleeve on its side wall. The sub-sleeve is used to accommodate the electrical connection end of the electrical terminal. The port of the sub-sleeve is a tapered groove structure with gradually increasing wire diameter, which is used to form an interference fit with the external plug-in cable. The base is bolted to the mounting slot of the transformer box, forming a sealed and waterproof structure in which the electrical terminals and the sleeve cooperate.

[0005] Furthermore, the outer circumferential surface of the tapered connecting boss is provided with at least two spaced annular sealing ridges along the axial direction, and the annular sealing ridges form a multi-stage interference seal with the inner wall of the insulating sleeve.

[0006] Furthermore, the root of the tapered connecting boss is provided with a radially outwardly extending limiting stop ring, and the bottom end face of the insulating sleeve abuts against the top surface of the limiting stop ring to limit the axial insertion depth of the insulating sleeve.

[0007] Furthermore, the bottom surface of the receiving platform is provided with concentric wedge-shaped grooves around each bolt hole, and a combined radial expansion sealing ring is embedded in the concentric wedge-shaped grooves; The combined radial expansion sealing ring includes an inner rigid wedge ring and an outer elastic sealing body. The inner circumferential surface of the rigid wedge ring is provided with an inclined surface that mates with the bolt head washer. When the bolts are tightened, the washer presses downward against the inclined surface, driving the rigid wedge ring to move radially outward, thereby causing the outer elastic seal to expand radially and press against the side wall of the mounting slot of the transformer box, forming a self-tightening sealing structure as the bolt preload increases.

[0008] Furthermore, the bottom surface of the receiving platform is also provided with an auxiliary annular sealing groove, in which a rubber strip is installed, and the rubber strip is in contact with the bottom of the outer elastic sealing body of the combined radial expansion sealing ring.

[0009] Furthermore, the top of the electrical connection post is provided with an outwardly expanding horn-shaped guide opening, and the electrical terminal is fixed in the horn-shaped guide opening by crimping or welding.

[0010] Furthermore, the outer wall of the tapered connecting boss is evenly distributed with several axial elastic locking tongues along the circumferential direction. One end of the axial elastic locking tongue is fixedly connected to the root of the tapered connecting boss, and the other end extends towards the insertion direction of the insulating sleeve and curves outward to form a hook. A ring-shaped locking groove is opened at the corresponding position on the bottom of the inner wall of the insulating sleeve. When the insulating sleeve is pushed into the predetermined position along the tapered connecting boss, the hook of the axial elastic locking tongue springs into the ring-shaped locking groove to form an axial one-way lock, preventing the insulating sleeve from coming out in the opposite direction.

[0011] Furthermore, the connection between the sub-sleeve and the main sleeve of the insulating sleeve is provided with a radial flexible pleated section. The wall thickness of the radial flexible pleated section is less than the wall thickness of other parts of the insulating sleeve, and its inner wall is provided with several axially extending corrugated deformation grooves. When the external plug cable is inserted into the tapered groove structure of the sub-sleeve, the radially flexible pleated section allows the sub-sleeve to produce radial micro-movement and axial yaw relative to the main sleeve to compensate for the bending stress of the cable. Meanwhile, a slidable locking nut is fitted on the outer circumferential surface of the radial flexible pleated section. The internal thread of the locking nut is matched with the external thread of the outer wall of the main sleeve. When the locking nut is tightened, the radial flexible pleated section is compressed and contracted inward.

[0012] Furthermore, the ratio of the axial length L1 of the insulating sleeve to the height H1 of the tapered connecting boss is between 1.5 and 2.0, and the ratio of the axial length L2 of the sub-sleeve to the maximum diameter Dmax of the tapered groove structure is between 0.8 and 1.2.

[0013] Furthermore, the interference fit between the insulating sleeve and the bottom of the tapered connecting boss is 0.2mm~0.5mm, and the interference fit between the tapered groove structure at the sub-sleeve port and the external plug-in cable is 0.1mm~0.3mm.

[0014] This invention provides a waterproof low-voltage cable connection assembly. By setting an insulating sleeve to fit onto a conical connecting boss on the base and encapsulating the electrical terminals of the conical connecting boss, the waterproof performance of the low-voltage cable connection assembly is improved. Based on the interference fit, multiple connection positions of the insulating sleeve are formed into a highly sealed structure, thereby ensuring the waterproof effect of the transformer tank. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the waterproof low-voltage cable connection assembly in an embodiment of the present invention; Figure 2 This is an exploded view of the waterproof low-voltage cable connection assembly in an embodiment of the present invention; Figure 3 This is a structural cross-sectional view of the waterproof low-voltage cable connection assembly in an embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] This invention provides a waterproof low-voltage cable connection assembly, comprising: a base 1, electrical terminals 4, an insulating sleeve 2, and a plug 3. The base 1 includes a receiving platform 11, a plurality of electrical connecting posts 13 disposed on the contact surface of the receiving platform 11, and a plurality of tapered connecting bosses 12 disposed on the outer side of the receiving platform 11. The receiving platform 11 is typically made into a flat or shaped base for supporting and positioning other components. The electrical connecting posts 13 are disposed on the surface of the receiving platform 11 that contacts the transformer housing, providing connection points to the internal electrical system of the transformer. The tapered connecting bosses 12 are disposed on the outer side of the receiving platform 11, and their tapered structure facilitates the installation of subsequent components and initial sealing. For example, the electrical connecting posts 13 can be threaded posts for easy connection with nuts inside the transformer; the tapered connecting bosses 12 can have a tapered structure to provide support.

[0019] The electrical terminal 4 is mounted on the tapered connecting boss 12, and the insulating sleeve 2 is fitted around the outside of the electrical terminal 4 to isolate the electrical terminal 4 from the external environment and provide electrical insulation protection. The insulating sleeve 2 can be fitted over the electrical terminal 4 and is held in position by its own elasticity or friction. The insulating sleeve 2 forms an interference fit with the bottom of the connecting boss, and the top of the insulating sleeve 2 forms an interference fit through the plug 3; the side wall of the insulating sleeve 2 has an outwardly extending sub-sleeve 21, which is used to accommodate the electrical connection end of the electrical terminal 4. The port of the sub-sleeve 21 is a tapered groove structure with gradually increasing wire diameter, which is used to form an interference fit with the external plug-in cable; the base 1 is locked to the mounting slot of the transformer box by bolts to form a sealed and waterproof structure for the electrical terminal 4 and the sleeve to fit together.

[0020] When the insulating sleeve 2 is pressed into the tapered connecting boss 12, the material undergoes elastic deformation, generating radial pressure and thus forming a seal. For example, the inner diameter of the insulating sleeve 2 can be slightly smaller than the outer diameter of the tapered connecting boss 12, achieving an interference fit through press fitting.

[0021] The top of the insulating sleeve 2 is press-fitted with a plug 3. This plug 3 seals the open end of the insulating sleeve 2, achieving a seal within the internal space. The plug 3 can be designed to have an press-fit with the inner wall of the top of the insulating sleeve 2, achieving installation and sealing by pressing or screwing. For example, the plug 3 can be a stopper with an outer diameter slightly larger than the inner diameter of the top of the insulating sleeve 2, forming a seal by pressing.

[0022] Furthermore, the sub-sleeve 21 is an extension of the insulating sleeve 2, and its structural design facilitates the access of external cables. The sub-sleeve 21 can be formed into the insulating sleeve 2, or connected to the main sleeve by means of bonding, welding, or other methods.

[0023] The sleeve 21 is used to accommodate the electrical connection terminal of the electrical terminal 4. The electrical connection terminal is the part of the electrical terminal 4 used for connection with an external cable. The internal space of the sleeve 21 is designed to accommodate the electrical connection terminal and provide it with protection and positioning.

[0024] The sleeve 21 port features a tapered groove structure with gradually increasing wire diameter. This tapered groove structure facilitates the insertion of external cables and guides subsequent sealing. The inner wall of the tapered groove can be machined into a tapered surface to reduce friction during insertion and removal.

[0025] The tapered groove structure is used to form an interference fit with the external plug-in cable. When the external cable is inserted into the tapered groove structure of the sub-sleeve 21, due to the size design of the tapered groove, an interference fit will be generated between the cable sheath and the inner wall of the tapered groove, thereby forming a radial seal.

[0026] The base 1 is bolted to the mounting slot of the transformer housing. The bolts pass through the pre-drilled holes in the base 1 and are screwed into the threaded holes on the transformer housing to fix the base 1 in the mounting slot. A flat washer can be placed between the bolt and the base 1 to distribute the pressure.

[0027] The interference fit and mechanical fixing ensure the reliability of the electrical connection and prevent moisture from seeping into the electrical connection area from the external environment, thereby improving the waterproof performance and operational safety of the entire low-voltage cable connection assembly.

[0028] Specifically, the outer circumferential surface of the tapered connecting boss 12 is provided with at least two spaced-apart annular sealing ridges along the axial direction. These annular sealing ridges form a multi-stage interference seal with the inner wall of the insulating sleeve 2. On the outer surface of the tapered connecting boss 12, there are annular protrusions spaced along its axial direction. These ridges can be integrally formed with the tapered connecting boss 12 or firmly attached to its surface by other means. Their main function is to form a multi-stage seal with the inner wall of the insulating sleeve 2. The cross-section of these annular sealing ridges can be designed in various shapes such as semi-circular, rectangular, or trapezoidal to optimize the contact pressure distribution with the inner wall of the insulating sleeve 2.

[0029] The number of annular sealing ridges is at least two, and can be set to two, three, or more depending on actual sealing requirements and space constraints to provide stronger sealing redundancy and reliability. The annular sealing ridges and the inner wall of the insulating sleeve 2 form a multi-stage interference seal. This refers to the formation of a multi-stage sealing structure that blocks fluid penetration through multiple independent sealing contact surfaces that undergo mutual compression deformation during assembly. This multi-stage sealing significantly improves the reliability and durability of the seal; even if one seal fails, the others can continue to function. The inner wall of the insulating sleeve 2 can be designed as a smooth cylindrical surface, relying on the elastic deformation of the annular sealing ridges to form an interference fit. Furthermore, the inner wall of the insulating sleeve 2 can also be designed with tiny grooves or guiding structures corresponding to the positions of the annular sealing ridges to assist in the positioning and sealing effect of the ridges, but the interference deformation of the ridges remains the primary factor.

[0030] By providing at least two spaced-apart annular sealing ridges along the axial direction on the outer periphery of the tapered connecting boss 12, a multi-stage interference seal is formed between the sealing sleeve 2 and the inner wall of the insulating sleeve 2. When the insulating sleeve 2 is pushed into the tapered connecting boss 12, each annular sealing ridge on the tapered connecting boss 12 will have an interference fit with the inner wall of the insulating sleeve 2, forming an independent sealing line. Due to the presence of at least two spaced-apart annular sealing ridges, multiple independent sealing barriers are formed between the insulating sleeve 2 and the tapered connecting boss 12. This multi-stage interference seal structure can effectively disperse sealing stress and provide redundant sealing protection. Even if one seal fails locally due to material aging, minor deformation, or external stress, the other sealing ridges can still maintain their sealing function, thereby ensuring the waterproof integrity of the entire connection assembly. This design significantly improves the reliability and durability of the seal and effectively prevents moisture and contaminants from entering the electrical connection area.

[0031] Furthermore, the tapered connecting boss 12 can be integrally injection molded from high-strength insulating plastic (such as polycarbonate or polyamide). The tapered connecting boss 12 has metal parts that are electrically connected to the electrical connecting post 13 to realize the electrical connection between the transformer box and the external cable.

[0032] Specifically, by providing at least two spaced-apart annular sealing ridges along the axial direction on the outer periphery of the tapered connecting boss 12, and forming a multi-stage interference seal with the inner wall of the insulating sleeve 2, the problem of insufficient reliability of a single interference fit seal is effectively solved. This multi-stage sealing structure provides multiple independent waterproof barriers, maintaining excellent sealing performance even during long-term operation or under complex conditions such as vibration and temperature changes. This significantly reduces the risk of moisture entering the cable connection assembly due to seal failure, thereby improving the waterproof reliability and service life of the entire low-voltage cable connection assembly.

[0033] Specifically, the root of the tapered connecting boss 12 is provided with a radially outwardly extending limiting stop ring 121, and the bottom end face of the insulating sleeve 2 abuts against the top surface of the limiting stop ring 121 to limit the axial insertion depth of the insulating sleeve 2.

[0034] The root of the tapered connecting boss 12 refers to the part where the tapered connecting boss 12 connects or transitions with the base 1, which can be the connection point between the tapered connecting boss 12 and the receiving platform 11. The radially outward extending limiting stop ring 121 is a structure that extends radially outward from the root of the tapered connecting boss 12. Its main function is to provide a physical blocking surface. This stop ring can be integrally formed at the root of the tapered connecting boss 12, for example, by injection molding or machining; or it can be manufactured separately and fixed to the root of the tapered connecting boss 12 by welding, threaded connection, or interference fit. The bottom end face of the insulating sleeve 2 is the lowest end face of the insulating sleeve 2 along its axial direction, usually the starting or ending interface for its engagement with the tapered connecting boss 12. This end face can be a flat annular surface or a structure with specific chamfers or grooves to facilitate assembly or sealing. The top surface of the limiting stop ring 121 is the surface of the radially outward extending limiting stop ring 121 facing the insertion direction of the insulating sleeve 2. The top surface can be flat, directly contacting the bottom end face of the insulating sleeve 2; it can also be designed with a certain slope or step to guide the insertion of the insulating sleeve 2 or provide a more stable contact. Contact refers to the bottom end face of the insulating sleeve 2 and the top surface of the limiting stop ring 121 contacting each other in the axial direction and applying pressure. This contact can be rigid or buffered by an intermediate elastic gasket. Limiting the axial insertion depth of the insulating sleeve 2 is achieved through the aforementioned contact relationship, ensuring that the insulating sleeve 2 does not exceed a preset position when axially inserted along the tapered connecting boss 12. This limitation ensures that the interference fit between the insulating sleeve 2 and the tapered connecting boss 12 is within the design range, avoiding excessive insertion depth that could lead to structural stress concentration or damage, while also preventing insufficient insertion from affecting the sealing effect.

[0035] By providing a radially outwardly extending limiting stop ring 121 at the root of the tapered connecting boss 12, and ensuring that the bottom end face of the insulating sleeve 2 abuts against the top surface of the limiting stop ring 121, the axial insertion depth of the insulating sleeve 2 is precisely controlled. During assembly, as the insulating sleeve 2 is inserted along the tapered connecting boss 12, its bottom end face gradually approaches and eventually contacts the top surface of the limiting stop ring 121. The root of the tapered connecting boss 12 can be integrally injection molded with the base 1, and a ring-shaped, outwardly radially protruding limiting stop ring 121 can be directly designed at this root. The top surface of the limiting stop ring 121 can be designed as a plane that matches the bottom end face of the insulating sleeve 2. During assembly, the insulating sleeve 2 is pushed axially along the tapered connecting boss 12 until its bottom end face is in close contact with the top surface of the limiting stop ring 121. For example, the limiting stop ring 121 can be made of the same insulating material as the base 1, such as reinforced polyamide or epoxy resin, to ensure sufficient mechanical strength and insulation performance. The bottom end face of the insulating sleeve 2 can be designed as a flat annular surface to form a stable surface contact with the top surface of the limiting stop ring 121.

[0036] Specifically, the bottom surface of the receiving platform 11 is provided with concentric wedge-shaped grooves around each bolt hole, and a combined radial expansion sealing ring is embedded in the concentric wedge-shaped grooves; the combined radial expansion sealing ring includes an inner rigid wedge-shaped ring and an outer elastic sealing body, and the inner circumferential surface of the rigid wedge-shaped ring is provided with an inclined surface that mates with the bolt head washer; when the bolt is tightened, the washer presses down on the inclined surface, driving the rigid wedge-shaped ring to move radially outward, thereby causing the outer elastic sealing body to expand radially and press against the side wall of the installation slot of the transformer box, forming a self-tightening sealing structure as the bolt preload increases.

[0037] The concentric wedge-shaped annular groove refers to an annular groove with a wedge-shaped cross-section, machined or molded on the bottom surface of the receiving platform 11 with the bolt hole as the center. The main function of this groove is to provide a precise installation space and support structure for the combined radial expansion seal ring, ensuring that the seal ring can be correctly positioned and effectively perform its radial expansion function. It can be formed on the metal or rigid plastic receiving platform 11 through precision machining, or it can be integrally formed during the injection molding of the receiving platform 11. The combined radial expansion seal ring is a device that converts axial pressure into radial expansion force through the movement of internal structural components, thereby achieving a seal.

[0038] When the bolt is tightened, the pressure of the bolt head washer first acts on the inclined surface of the rigid ring. The rigid ring converts the axial pressure into radial thrust and guides the outer elastic seal to expand outward. This rigid ring is typically made of a material with sufficient strength and rigidity, such as stainless steel, brass, or high-strength engineering plastics.

[0039] The outer elastic seal is the component in the combined radial expansion seal ring that directly contacts the side wall of the transformer tank mounting slot to form a seal. Its main characteristics are good elasticity and compressive deformation capacity, which allows it to expand under pressure and tightly fit against the side wall of the mounting slot, filling tiny gaps and thus achieving a reliable fluid seal.

[0040] The inner circumferential surface of the rigid wedge ring has an inclined surface that mates with the bolt head washer. This inclined surface is a specific structure on the rigid wedge ring used to receive the pressure of the bolt head washer. Its design purpose is to effectively decompose and convert the axial locking force of the bolt into a radial component, thereby driving the rigid wedge ring to move radially outward.

[0041] Furthermore, the angle and surface finish of the bevel will affect the conversion efficiency and the expansion performance of the seal. This bevel can be formed on the inner circumferential surface of the rigid wedge ring by die forming or machining.

[0042] When the bolt is tightened, the washer beneath the bolt head applies downward pressure. Due to the beveled surface on the inner circumference of the rigid wedge ring, the axial pressure of the washer is guided by the bevel, generating a radial component force. This radial component force pushes the rigid wedge ring outward. The radial movement of the rigid wedge ring then compresses the elastic seal on its outer side, forcing the elastic seal to expand radially. The expanded elastic seal presses tightly against the sidewall of the mounting slot in the transformer tank, thus forming a tight seal. This design allows the sealing force to increase with the bolt preload, creating a "self-tightening" effect that improves the reliability and durability of the seal.

[0043] Specifically, the bottom surface of the receiving platform 11 is also provided with an auxiliary annular sealing groove, and a rubber strip is installed in the auxiliary annular sealing groove. The rubber strip is in contact with the bottom of the outer elastic sealing body of the combined radial expansion sealing ring.

[0044] The auxiliary annular sealing groove refers to a specially designed annular groove on the bottom surface of the receiving platform 11, which provides a stable installation space and positioning structure for the rubber strip. This groove can be formed directly on the material of the receiving platform 11 by machining, such as milling or molding. Its cross-sectional shape can be designed as rectangular, U-shaped, or V-shaped to accommodate rubber strips of different shapes and ensure that the rubber strip can be securely installed within it, preventing displacement.

[0045] This can be achieved by prefabricating an annular strip whose cross-sectional dimensions and shape match the auxiliary annular sealing groove for easy installation. The rubber strip contacts the bottom of the outer elastic sealing body of the combined radial expansion sealing ring, meaning that the position and depth of the auxiliary annular sealing groove are carefully designed so that the top surface or side of the rubber strip installed therein can fit tightly against or maintain a slight gap with the bottom surface of the outer elastic sealing body of the combined radial expansion sealing ring.

[0046] A two-stage sealing system was constructed by adding an auxiliary annular sealing groove and installing a rubber strip on the bottom surface of the receiving platform 11, and making it contact the bottom of the outer elastic sealing body of the combined radial expansion sealing ring.

[0047] Specifically, in this embodiment, the bottom surface of the receiving platform 11 can be made of high-strength engineering plastic, and the auxiliary annular sealing groove can be designed as an annular groove machined into the bottom surface of the receiving platform 11. Its cross-sectional shape is rectangular, and its depth and width are optimized to accommodate the rubber strip. The rubber strip can be made of an acrylic-based rubber material, pre-formed into an annular shape, with its outer diameter matching the inner diameter of the auxiliary annular sealing groove. The inner diameter is coordinated with the distribution of bolt holes to ensure it can be tightly installed within the auxiliary annular sealing groove. During installation, the rubber strip is placed in the auxiliary annular sealing groove, and its top surface is tightly fitted with the bottom surface of the outer elastic sealing body of the combined radial expansion sealing ring, thereby effectively preventing further moisture penetration and achieving dynamic replenishment and reinforcement of the seal.

[0048] Specifically, the top of the electrical connecting post 13 is provided with an outwardly expanding trumpet-shaped guide opening, and the electrical terminal 4 is fixed in the trumpet-shaped guide opening by crimping or welding. The outwardly expanding trumpet-shaped guide opening at the top of the electrical connecting post 13 is a structure with a gradually widening opening, and its main function is to guide the electrical terminal 4 smoothly into the electrical connecting post 13, reducing alignment difficulty and improving connection efficiency.

[0049] Furthermore, the guide opening can adopt a smooth conical or arc-shaped transition to ensure that the electrical terminal 4 can slide smoothly during insertion. In addition, the guide opening can also be designed as a multi-segment conical shape to accommodate insertion at different angles, further enhancing the guiding effect. The electrical terminal 4 is fixed inside the flared guide opening by crimping or welding. Crimping and welding are two common methods of electrical connection fixing, used to ensure mechanical fixation and electrical conductivity between the electrical terminal 4 and the electrical connection post 13. Crimping can be performed by cold-pressing and deforming the electrical terminal 4 and the flared guide opening with a special crimping tool, making them tightly bonded to form a reliable mechanical and electrical connection. Crimping can take various forms such as hexagonal crimping, four-point crimping, or die crimping. Welding can connect the electrical terminal 4 and the flared guide opening by melting solder to form a metallurgical bond. Welding can be performed by resistance welding, laser welding, or brazing to ensure low resistance and high strength of the connection.

[0050] Specifically, the top of the electrical connection post 13 can be machined into a flared guide opening with a cone angle of approximately 30 degrees, the maximum opening diameter of which is 2mm to 3mm larger than the outer diameter of the electrical terminal 4. After the electrical terminal 4 is inserted into this guide opening, a ring-shaped pressing die can be used to radially press the outer wall of the guide opening, causing the guide opening material to shrink inward and tightly enclose the electrical terminal 4, forming a strong mechanical and electrical connection. Alternatively, solder paste can be pre-coated onto the inner wall of the guide opening. After inserting the electrical terminal 4, local heating, such as induction heating or laser heating, can melt the solder, welding the electrical terminal 4 to the guide opening.

[0051] Through the above technical solution, the outwardly expanding flared guide opening at the top of the electrical connection post 13 greatly simplifies the alignment and insertion process of the electrical terminal 4 and the electrical connection post 13, effectively avoiding operational difficulties and low connection efficiency caused by inaccurate alignment. Simultaneously, fixing the electrical terminal 4 within the flared guide opening using crimping or welding ensures the mechanical strength and electrical reliability of the connection, reduces contact resistance, and improves the stability of current transmission. This design not only improves the assembly efficiency and connection quality of the component but also enhances the reliability of the waterproof low-voltage cable connection assembly during long-term operation.

[0052] In response, this application further proposes that the outer wall of the tapered connecting boss 12 has a plurality of axial elastic locking tongues 122 evenly distributed along the circumferential direction. One end of the axial elastic locking tongue 122 is fixedly connected to the root of the tapered connecting boss 12, and the other end extends toward the insertion direction of the insulating sleeve 2 and curves outward to form a hook. A corresponding annular locking groove is provided at the bottom of the inner wall of the insulating sleeve 2. When the insulating sleeve 2 is pushed into the predetermined position along the tapered connecting boss 12, the hook of the axial elastic locking tongue 122 springs into the annular locking groove to form an axial one-way lock, preventing the insulating sleeve 2 from falling out in the opposite direction.

[0053] Furthermore, the axial elastic locking tongue 122 is an elastic structure disposed on the outer wall of the conical connecting boss 12. It extends axially and has a certain elastic deformation capability. The axial elastic locking tongue 122 can be made of a material integrally formed with the conical connecting boss 12, such as injection-molded high-strength engineering plastic, or an independent elastic metal sheet can be fixed to the conical connecting boss 12 by riveting, welding, or other methods. Its main function is to provide elastic deformation during the insertion of the insulating sleeve 2 and to achieve locking after reaching the predetermined position.

[0054] The hook is the end structure of the axial elastic locking tongue 122, characterized by its outward curve, forming a protrusion capable of engaging with the annular locking groove. The hook can be designed with a bevel to allow the insulating sleeve 2 to slide smoothly during insertion and to provide reliable axial blocking after springing into the annular locking groove. For example, the hook can be barbed or wedge-shaped. The annular locking groove is a groove structure formed at the bottom of the inner wall of the insulating sleeve 2, its position corresponding to the hook of the axial elastic locking tongue 122 on the conical connecting boss 12. This locking groove can be a continuous annular groove or composed of multiple spaced grooves. Its main function is to provide a receiving space for the hook of the axial elastic locking tongue 122, forming a mechanical lock when the hook springs into it. Axial one-way locking means that the engagement of the hook of the axial elastic locking tongue 122 with the annular locking groove allows the insulating sleeve 2 to move smoothly in the axial insertion direction, but is hindered in the reverse direction (disengagement direction), preventing easy disengagement. This locking mechanism is mechanical and, once formed, provides a stable axial fixing force. Preventing the insulating sleeve 2 from reversing out is a direct effect of the axial one-way locking, ensuring that the insulating sleeve 2 can be firmly held in the predetermined position on the tapered connecting boss 12 when subjected to external axial tension or vibration, thereby maintaining the sealing effect of the interference fit and the stability of the electrical connection.

[0055] Furthermore, a plurality of axially elastic locking tongues 122 are evenly distributed along the circumferential direction on the outer wall of the conical connecting boss 12. One end of these locking tongues is fixedly connected to the root of the conical connecting boss 12, and the other end extends toward the insertion direction of the insulating sleeve 2 and curves outward to form a hook. At the same time, an annular locking groove is provided at the corresponding position on the bottom of the inner wall of the insulating sleeve 2. When the insulating sleeve 2 is pushed in along the conical connecting boss 12, the inner wall of the insulating sleeve 2 will first contact the hook of the axially elastic locking tongue 122. Since the hook curves outward, the insulating sleeve 2 will squeeze the axially elastic locking tongue 122 during insertion, causing it to elastically deform inward. As the insulating sleeve 2 continues to be pushed in, when its bottom reaches the predetermined position, the hook of the axially elastic locking tongue 122 will align with the annular locking groove at the bottom of the inner wall of the insulating sleeve 2. At this time, due to the elastic restoring force, the hook will immediately spring into the annular locking groove. Once the hook engages with the annular locking groove, its outward-curving structure mechanically locks against the edge of the groove, creating a one-way axial lock. This locking mechanism effectively prevents the insulating sleeve 2 from moving in the opposite axial direction (i.e., the disengagement direction), ensuring that the insulating sleeve 2 is firmly fixed to the tapered connecting boss 12 even under vibration, impact, or external tension. This mechanical locking, combined with the existing interference fit, not only enhances the axial fixing capability of the insulating sleeve 2 but also further guarantees the long-term reliability of the sealed and waterproof structure between the electrical terminal 4 and the sleeve.

[0056] Furthermore, the tapered connecting boss 12 can be integrally molded from high-strength polyamide (PA) material using an injection molding process, with multiple axially elastic locking tongues 122 integrated on its outer side wall. These multiple axially elastic locking tongues 122 can be designed as a cantilever beam structure with a certain thickness and length, with their free ends bent outwards to form hooks. The inner surface of the hooks can be designed as a slope, while the outer surface is a vertical surface. The insulating sleeve 2 can be made of elastic materials such as silicone rubber or EPDM rubber, with a continuous annular groove formed at the bottom of its inner wall through a mold as an annular locking groove. During assembly, the operator pushes the insulating sleeve 2 axially along the tapered connecting boss 12. The inner wall of the insulating sleeve 2 gradually compresses the axially elastic locking tongues 122. When the insulating sleeve 2 is pushed to a predetermined position where its bottom abuts against the limiting stop ring 121 (if present) of the tapered connecting boss 12, the hooks of the axially elastic locking tongues 122 precisely align and spring into the annular locking groove on the inner wall of the insulating sleeve 2.

[0057] Through the above technical solution, in the waterproof low-voltage cable connection assembly, the insulating sleeve 2 and the tapered connecting boss 12 not only achieve a seal through an interference fit, but also achieve axial one-way locking of the insulating sleeve 2 through the cooperation of the axial elastic locking tongue 122 and the annular locking groove. This locking mechanism significantly enhances the mechanical fixing strength of the insulating sleeve 2, effectively preventing the insulating sleeve 2 from loosening or accidentally coming off when subjected to vibration, impact, or external axial tension. This greatly improves the overall reliability and stability of the cable connection assembly, ensuring that the sealed and waterproof structure of the electrical terminal 4 and the sleeve maintains its integrity during long-term operation, thereby avoiding electrical faults or water leakage problems caused by the insulating sleeve 2 coming off, and extending the service life of the assembly.

[0058] Specifically, at the connection between the sub-sleeve 21 and the main sleeve of the insulating sleeve 2, a radially flexible corrugated section 211 is provided. The wall thickness of the radially flexible corrugated section 211 is less than the wall thickness of other parts of the insulating sleeve 2, and its inner wall is provided with several axially extending corrugated deformation grooves. When the external plug-in cable is inserted into the conical groove structure of the sub-sleeve 21, the radially flexible corrugated section 211 allows the sub-sleeve 21 to produce radial micro-movement and axial sway relative to the main sleeve to compensate for the bending stress of the cable. At the same time, a slidable locking nut is fitted on the outer circumferential surface of the radially flexible corrugated section 211. The internal thread of the locking nut is matched with the external thread of the outer wall of the main sleeve. When the locking nut is tightened, the radially flexible corrugated section 211 is compressed inward to enhance the clamping force and sealing performance of the cable.

[0059] Furthermore, the radially flexible corrugated section 211 is a special structural region at the connection between the sub-sleeve 21 and the main sleeve of the insulating sleeve 2, and its main function is to provide local elastic deformation capability. This section can be designed as a corrugated tubular structure, or a thin-walled region can be formed through material selection and geometric optimization, thereby providing a certain degree of flexibility in the radial and axial directions. The wall thickness of the radially flexible corrugated section 211 is less than the wall thickness of other parts of the insulating sleeve 2. This design is to further enhance the flexibility of the radially flexible corrugated section 211. By reducing the wall thickness, the stiffness of this region can be reduced, making it easier for it to undergo elastic deformation under external stress. For example, in the injection molding process, a thinner wall thickness can be formed by the local shrinkage of the mold cavity; or, in subsequent processing, some material can be removed by turning, milling, etc., to achieve the required wall thickness. Its inner wall is provided with several axially extending corrugated deformation grooves. These deformation grooves are set on the inner wall of the radially flexible corrugated section 211, and their function is to guide and control the deformation mode of the flexible section, so that it can be more uniform and controllable during radial shrinkage or axial yaw. Meanwhile, the corrugated structure itself increases the overall flexibility of the flexible segment. For example, these deformation grooves can be integrally formed during injection molding using a mold; or, after the flexible segment is formed, they can be formed by laser etching or mechanical imprinting. The sliding locking nut is a ring-shaped fastener designed to slide on the outer circumferential surface of the radially flexible corrugated segment 211. Its main function is to apply radial pressure to the flexible segment when tightened, thereby enhancing the clamping force and sealing of the cable.

[0060] Furthermore, the threads on the outer wall of the main sleeve can be integrally formed with the main sleeve, or they can be formed by machining (such as turning).

[0061] Specifically, by providing a radially flexible corrugated section 211 at the connection between the sub-sleeve 21 and the main sleeve of the insulating sleeve 2, and supplementing it with a design that reduces wall thickness and incorporates an axial corrugated deformation groove, this area possesses significant elastic deformation capability. When the external plug-in cable is inserted into the tapered groove structure of the sub-sleeve 21 and forms an interference fit, even if the cable is subjected to bending stress, vibration, or slight axial / radial displacement, the radially flexible corrugated section 211 allows the sub-sleeve 21 to undergo radial micro-movement and axial yaw relative to the main sleeve. This flexible connection effectively compensates for the dynamic stress of the cable, avoids potential damage to the cable or connection assembly caused by stress concentration, and maintains the initial interference seal.

[0062] Furthermore, by fitting a sliding locking nut onto the outer circumference of the radially flexible corrugated section 211, with its internal thread engaging with the external thread of the main sleeve's outer wall, the user can apply radial pressure to the radially flexible corrugated section 211 by tightening the locking nut. This pressure causes the flexible corrugated section 211 to contract inward, further enhancing its gripping force on the externally plugged cable. This provides additional radial sealing pressure on top of the original interference fit, significantly improving the sealing reliability and pull-out resistance of the connection assembly. Overall, this solution combines flexible compensation with adjustable enhanced sealing, enabling the cable connection to maintain stable and reliable electrical connection and waterproof performance even under dynamic stress environments.

[0063] Specifically, the connection between the sub-sleeve 21 and the main sleeve of the insulating sleeve 2 can be made of an integrally injection-molded radially flexible corrugated section 211. The material of the flexible corrugated section 211 can be a thermoplastic elastomer with good elasticity and weather resistance. The axially extending corrugated deformation grooves on its inner wall can be designed as a series of equally spaced annular corrugations. These corrugations extend continuously in the axial direction to ensure uniform deformation during radial contraction.

[0064] The sliding locking nut can be injection molded from high-strength engineering plastics (such as polyamide PA66), and its internal thread matches the pre-machined external thread on the outer wall of the main sleeve. When the external plug-in cable is inserted into the tapered groove structure of the sub-sleeve 21, the locking nut is tightened manually or with a tool. The internal thread of the locking nut engages with the external thread on the outer wall of the main sleeve, and gradually applies radial pressure to the radially flexible pleated section 211, causing the flexible pleated section 211 to contract radially inward and tightly grip the cable, thereby achieving an enhanced sealing and gripping effect.

[0065] Specifically, in the waterproof low-voltage cable connection assembly, the radially flexible corrugated section 211 at the connection between the sub-sleeve 21 and the main sleeve of the insulating sleeve 2, combined with its reduced wall thickness and corrugated deformation groove on the inner wall, allows the sub-sleeve 21 to effectively compensate for bending stress, vibration, or slight displacement that may occur during the installation or operation of the external plug-in cable. This significantly reduces the risk of seal failure or mechanical damage at the cable connection due to dynamic stress. Simultaneously, the sliding locking nut, threaded into the outer wall of the main sleeve, allows for active adjustment of the pressure on the radially flexible corrugated section 211, further enhancing the clamping force and sealing performance of the cable on top of the existing interference fit. This design not only improves the long-term reliability and waterproof performance of the connection assembly under complex operating conditions but also extends the service life of the assembly, ensuring the stability and safety of the electrical connection.

[0066] Specifically, the connection between the sub-sleeve 21 and the main sleeve of the insulating sleeve 2 is provided with a radially flexible corrugated section 211. The wall thickness of the radially flexible corrugated section 211 is less than the wall thickness of other parts of the insulating sleeve 2, and its inner wall is provided with several axially extending corrugated deformation grooves. When the external plug-in cable is inserted into the conical groove structure of the sub-sleeve 21, the radially flexible corrugated section 211 allows the sub-sleeve 21 to produce radial micro-movement and axial sway relative to the main sleeve to compensate for the bending stress of the cable. At the same time, a sliding locking nut is fitted on the outer circumferential surface of the radially flexible corrugated section 211. The internal thread of the locking nut is matched with the external thread of the outer wall of the main sleeve. When the locking nut is tightened, the radially flexible corrugated section 211 is compressed inward to enhance the clamping force and sealing performance of the cable.

[0067] Specifically, the ratio of the axial length L1 of the insulating sleeve 2 to the height H1 of the tapered connecting boss 12 is 1.5~2.0:1, and the ratio of the axial length L2 of the sub-sleeve 21 to the maximum diameter Dmax of the tapered groove structure is 0.8~1.2:1. The ratio of the axial length L1 of the insulating sleeve 2 to the height H1 of the tapered connecting boss 12 is 1.5~2.0:1, which defines the degree of matching of the axial dimensions between the insulating sleeve 2 and the tapered connecting boss 12. This ratio is set to ensure that the insulating sleeve 2 can fully cover the tapered connecting boss 12, forming a stable and reliable interference fit, while reserving sufficient space for other functional structures inside the insulating sleeve 2 (such as the radially flexible pleated section 211). This ratio can be achieved through precise mold design and injection molding process. For example, when the height H1 of the tapered connecting boss 12 is 20mm, the axial length L1 of the insulating sleeve 2 can be designed to be between 30mm and 40mm.

[0068] The ratio of the axial length L2 of the sub-sleeve 21 to the maximum diameter Dmax of the tapered groove structure is 0.8 to 1.2:1. This ratio defines the degree of matching between the axial dimension of the sub-sleeve 21 and the maximum diameter of its internal tapered groove structure. This ratio is designed to optimize the insertion depth and clamping force of the external plug-in cable within the tapered groove structure, ensuring an effective interference fit between the cable and the tapered groove structure, thereby achieving reliable electrical connection and sealing. This ratio can also be controlled through precision machining or mold design. For example, when the maximum diameter Dmax of the tapered groove structure is 10 mm, the axial length L2 of the sub-sleeve 21 can be designed to be between 8 mm and 12 mm.

[0069] The solution in this application optimizes the structural dimensions of the entire waterproof low-voltage cable connection assembly by precisely defining the ratio of the axial length L1 of the insulating sleeve 2 to the height H1 of the tapered connecting boss 12, and the ratio of the axial length L2 of the sub-sleeve 21 to the maximum diameter Dmax of the tapered groove structure. The specific length ratio between the insulating sleeve 2 and the tapered connecting boss 12 ensures a full axial fit and stable interference seal, avoiding seal failure due to insufficient length or material waste and structural redundancy due to excessive length. Simultaneously, the ratio of the axial length L2 of the sub-sleeve 21 to the maximum diameter Dmax of the tapered groove structure precisely controls the insertion depth and clamping effect of the external plug-in cable within the sub-sleeve 21. This proportional design allows the tapered groove structure to provide optimal radial compressive force to the cable, enhancing the sealing performance and connection stability between the cable and the sub-sleeve 21. These precise dimensional proportions work together to not only optimize the compensation effect of the radial flexible pleated section 211 on the bending stress of the cable, but also ensure that the locking nut can more effectively compress the radial flexible pleated section 211 when tightened, thereby maintaining excellent sealing performance and connection reliability under various working conditions.

[0070] Specifically, in this embodiment, the height H1 of the tapered connecting boss 12 can be set to 25mm, and the axial length L1 of the insulating sleeve 2 can be designed to be 40mm. In this case, the ratio of L1 to H1 is 1.6:1, falling within the range of 1.5 to 2.0:1. Simultaneously, if the maximum diameter Dmax of the tapered groove structure is 15mm, the axial length L2 of the sub-sleeve 21 can be designed to be 15mm. In this case, the ratio of L2 to Dmax is 1.0:1, falling within the range of 0.8 to 1.2:1. This dimensional configuration allows the insulating sleeve 2 to be securely mounted on the tapered connecting boss 12 and provides sufficient deformation space for the radially flexible corrugated section 211. At the same time, the sub-sleeve 21 can provide appropriate clamping force for the inserted cable, ensuring the reliability and sealing of the connection.

[0071] Through the above technical solution, the interference fit between the insulating sleeve 2 and the bottom of the tapered connecting boss 12, as well as the interference fit between the tapered groove structure at the port of the sub-sleeve 21 and the external plug-in cable, are precisely quantified. This application can ensure that the connection assembly forms a stable and reliable seal at different connection interfaces. This quantitative design avoids seal failure due to insufficient interference fit, and also avoids stress concentration, assembly difficulties, or material damage to components that may be caused by excessive interference fit. By optimizing these key fitting parameters, the waterproof performance and long-term operational reliability of the entire waterproof low-voltage cable connection assembly are significantly improved. Especially in humid or water-rich environments, it can effectively prevent moisture intrusion and ensure the safety and stability of the electrical connection.

[0072] Furthermore, the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A waterproof low-voltage cable connection assembly, characterized in that, The waterproof low-voltage cable connection assembly includes: a base, electrical terminals, an insulating sleeve, and a plug. The base includes a receiving platform, a plurality of electrical connection posts disposed on the contact surface of the receiving platform, and a plurality of conical connection protrusions disposed on the outer side of the receiving platform. The electrical terminal is mounted on the tapered connecting boss, and the insulating sleeve is sleeved on the outside of the electrical terminal. The insulating sleeve forms an interference fit with the bottom of the connecting boss, and the top of the insulating sleeve forms an interference fit through a plug. The insulating sleeve has an outwardly extending sub-sleeve on its side wall. The sub-sleeve is used to accommodate the electrical connection end of the electrical terminal. The port of the sub-sleeve is a tapered groove structure with gradually increasing wire diameter, which is used to form an interference fit with the external plug-in cable. The base is bolted to the mounting slot of the transformer box, forming a sealed and waterproof structure in which the electrical terminals and the sleeve cooperate.

2. The waterproof low-voltage cable connection assembly as described in claim 1, characterized in that, The outer circumferential surface of the tapered connecting boss is provided with at least two spaced annular sealing ridges along the axial direction, and the annular sealing ridges form a multi-stage interference seal with the inner wall of the insulating sleeve.

3. The waterproof low-voltage cable connection assembly as described in claim 2, characterized in that, The base of the tapered connecting boss is provided with a radially outwardly extending limiting stop ring, and the bottom end face of the insulating sleeve abuts against the top surface of the limiting stop ring to limit the axial insertion depth of the insulating sleeve.

4. The waterproof low-voltage cable connection assembly as described in claim 1, characterized in that, The bottom surface of the receiving platform is provided with concentric wedge-shaped grooves around each bolt hole, and a combined radial expansion sealing ring is embedded in the concentric wedge-shaped grooves. The combined radial expansion sealing ring includes an inner rigid wedge ring and an outer elastic sealing body. The inner circumferential surface of the rigid wedge ring is provided with an inclined surface that mates with the bolt head washer. When the bolts are tightened, the washer presses downward against the inclined surface, driving the rigid wedge ring to move radially outward, thereby causing the outer elastic seal to expand radially and press against the side wall of the mounting slot of the transformer box, forming a self-tightening sealing structure as the bolt preload increases.

5. The waterproof low-voltage cable connection assembly as described in claim 4, characterized in that, The bottom surface of the receiving platform is also provided with an auxiliary annular sealing groove, and a rubber strip is installed in the auxiliary annular sealing groove. The rubber strip is in contact with the bottom of the outer elastic sealing body of the combined radial expansion sealing ring.

6. The waterproof low-voltage cable connection assembly as described in claim 1, characterized in that, The top of the electrical connection post is provided with an outwardly expanding horn-shaped guide opening, and the electrical terminal is fixed in the horn-shaped guide opening by crimping or welding.

7. The waterproof low-voltage cable connection assembly as described in claim 1, characterized in that, The outer wall of the tapered connecting boss has several axial elastic locking tongues evenly distributed along the circumferential direction. One end of the axial elastic locking tongue is fixedly connected to the root of the tapered connecting boss, and the other end extends toward the insertion direction of the insulating sleeve and curves outward to form a hook. An annular locking groove is provided at the bottom of the inner wall of the insulating sleeve. When the insulating sleeve is pushed into the predetermined position along the conical connecting boss, the hook of the axial elastic locking tongue springs into the annular locking groove to form an axial one-way lock.

8. The waterproof low-voltage cable connection assembly as described in claim 1, characterized in that, The connection between the sub-sleeve and the main sleeve of the insulating sleeve is provided with a radial flexible pleated section. The wall thickness of the radial flexible pleated section is less than the wall thickness of other parts of the insulating sleeve, and its inner wall is provided with several axially extending corrugated deformation grooves. When the external plug cable is inserted into the tapered groove structure of the sub-sleeve, the radially flexible pleated section allows the sub-sleeve to produce radial micro-movement and axial yaw relative to the main sleeve to compensate for the bending stress of the cable. Meanwhile, a slidable locking nut is fitted on the outer circumferential surface of the radial flexible pleated section. The internal thread of the locking nut is matched with the external thread of the outer wall of the main sleeve. When the locking nut is tightened, the radial flexible pleated section is compressed and contracted inward.

9. The waterproof low-voltage cable connection assembly as described in claim 8, characterized in that, The ratio of the axial length L1 of the insulating sleeve to the height H1 of the tapered connecting boss is between 1.5 and 2.0, and the ratio of the axial length L2 of the sub-sleeve to the maximum diameter Dmax of the tapered groove structure is between 0.8 and 1.

2.

10. The waterproof low-voltage cable connection assembly as described in claim 1, characterized in that, The interference fit between the insulating sleeve and the bottom of the tapered connecting boss is 0.2mm~0.5mm, and the interference fit between the tapered groove structure at the sub-sleeve port and the external plug-in cable is 0.1mm~0.3mm.

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