A sealing structure for a liquid injection hole

Abstract

The utility model discloses a kind of sealing structure of liquid injection hole, it is related to battery technical field, including cover plate main body and sealing structure, the cover plate main body is equipped with cover plate liquid injection hole, the cover plate main body is equipped with liquid injection hole and the first annular protrusion and second annular protrusion located in liquid injection hole inner wall, the sealing structure includes sealing screw nail and rubber peg, the sealing screw nail is equipped with outer thread and located in the positioning portion of peg body bottom, the top of the sealing screw nail is equipped with recess for assembly and secondary disassembly, the lower half of the rubber peg is hollow cylindrical structure, the upper half of the rubber peg is the rubber gasket integrally formed with the lower half, the rubber peg includes lower half and upper half, the lower half is hollow cylindrical structure and inner wall is equipped with internal thread. The utility model aims at solving the problems of poor sealing reliability, complex processing, low operation efficiency and the like in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a liquid injection hole sealing structure. Background Technology

[0002] In the production and use of aluminum-cased batteries, the sealing performance of the injection hole is crucial, directly affecting the battery's safety and lifespan. Existing technology, such as patent CN215896640U, discloses a non-welded cover plate injection structure. This structure includes an end cap and a sealing element. The end cap has an injection hole, and the sealing element is used to seal the injection hole. The sealing element includes a screw and a rubber ring. The screw is threaded to the injection hole, and a nut is provided at the tip of the screw to compress the rubber ring. A sealing plug is connected to the end of the screw through an adhesive layer, and the sealing plug fits against the wall of the injection hole. However, the aforementioned existing technology has obvious drawbacks: First, the direct threaded connection between the metal screw and the injection hole can easily introduce foreign metal objects, posing a safety hazard to the battery. Furthermore, the hard threaded connection between the metals may fail due to vibration, causing the injection hole to lose its sealing effect. Second, the sealing structure includes multiple components such as sealing screws, sealing plugs, sealing rings, and adhesive layers, making the processing steps complex and requiring many parts, which increases production costs and assembly difficulty. Third, during the insertion and removal of the injection screws before and after formation, the threads of the injection hole are prone to sealing failure, which may introduce moisture during battery aging and transportation. At the same time, the large friction generated by the threads will affect the working efficiency of the screw removal machine. Utility Model Content

[0003] Technical problem to be solved by the utility model

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a sealing structure for the injection hole to solve the problems of poor sealing reliability, complex processing, and low operating efficiency in the prior art.

[0005] Technical solution

[0006] To solve the above problems, the technical solution provided by this utility model is as follows:

[0007] A liquid injection hole sealing structure includes a cover plate body and a sealing structure. The cover plate body has a liquid injection hole and a first annular protrusion and a second annular protrusion located on the inner wall of the liquid injection hole. The sealing structure includes a sealing screw and a rubber nail. The sealing screw has external threads and a positioning part located at the bottom of the nail body. The top of the sealing screw has a groove for assembly and secondary disassembly. The lower half of the rubber nail is a hollow cylindrical structure, and the upper half of the rubber nail is a rubber gasket integrally formed with the lower half. The rubber nail includes a lower half and an upper half. The lower half is a hollow cylindrical structure and has internal threads on its inner wall.

[0008] By utilizing the integral molding characteristics of the rubber nails and the ring-shaped protrusion design, direct contact with metal parts (such as screws) is reduced, thereby reducing the risk of introducing metal foreign objects and improving battery safety and lifespan. At the same time, the overall structure only includes core components such as the cover plate body, sealing screws, and rubber nails, simplifying the production process, reducing assembly difficulty and cost, and the top groove design facilitates quick assembly and secondary disassembly, significantly improving operational efficiency and preventing moisture intrusion or electrolyte leakage due to seal failure during formation, aging, or transportation.

[0009] Alternatively, the sealing screw may be made of PPS with 30% glass fiber.

[0010] The sealing screws are made of PPS (polyphenylene sulfide) with 30% glass fiber. Their core function is to address the safety risks associated with metal screws and improve overall sealing reliability. Eliminating the risk of metal foreign objects: As a non-metallic material, PPS avoids the risk of metal fragments introduced into the battery during screw engagement, significantly improving battery safety. Optimizing sealing compatibility: When PPS engages with the internal threads of the rubber screw, its hardness (Rockwell M100) is higher than rubber but lower than metal. This allows it to compensate for assembly tolerances through elastic deformation during tightening, preventing rubber gasket breakage due to overpressure and creating a more uniform sealing interface. Lightweight and corrosion-resistant: Compared to metal, PPS has a density of only 1.54 g / cm³, reducing component weight. It is also resistant to electrolyte and acid / alkali corrosion, showing no degradation over long-term use and extending seal life.

[0011] Optionally, the cavity of the lower half of the rubber nail has internal threads that match the external threads of the sealing screw.

[0012] Achieving non-metallic elastic locking and dynamic sealing compensation: Eliminating the risk of metal-to-metal contact: Through the engagement of the rubber internal thread and the PPS screw, debris generated by metal-to-metal friction is completely avoided from contaminating the battery interior, ensuring safety from the source. Adaptive sealing enhancement: The rubber internal thread undergoes elastic deformation during tightening, tightly wrapping the screw's external thread, filling microscopic assembly gaps, and forming the first leak-proof barrier; simultaneously, the thread lead converts the axial screwing force into radial expansion force, driving the lower half of the rubber nail to press against the double-ring protrusions on the inner wall of the injection hole, establishing a second seal. Optimized operational efficiency: The threaded engagement structure provides controllable progressive clamping (not a one-time snap-fit), allowing precise adjustment of the sealing pressure, and disassembly can be achieved by reverse rotation, significantly reducing the working resistance of the nail puller.

[0013] Optionally, when the sealing screw is screwed into the rubber nail, the lower half is squeezed by the first annular protrusion and the second annular protrusion to expand laterally and form a first sealing surface, while the upper half is compressed longitudinally by the positioning part to form a second sealing surface.

[0014] Redundant sealing guarantee: The upper annular gasket is longitudinally compressed to form a second sealing surface, which together with the lower annular gasket to form a first sealing surface, constitutes an orthogonal bidirectional sealing barrier. Even if one side fails (such as vibration causing the lateral seal to loosen), the axial compression seal can still maintain leakage prevention. The annular gasket also acts as a stress buffer layer to disperse the local pressure when the screw is screwed in and prevent the rubber nail from tearing. Adaptive to changes in working conditions: The double annular protrusions compress the lower part of the rubber nail to form a geometric constraint, forcing the rubber to expand in a limited space (rather than deforming freely), ensuring that the sealing pressure is accurately applied to the high-risk leakage area on the inner wall of the injection hole.

[0015] Optionally, the height difference between the first annular protrusion and the second annular protrusion is 0.2-0.5 mm, causing the lower half of the rubber nail to undergo gradient compression deformation.

[0016] Dynamic sealing pressure optimization: A stepped compression space is formed by the height difference of the two protrusions (e.g., 0.3mm), causing non-uniform deformation of the lower half of the rubber nail when the screw is screwed in—the higher protrusion preferentially compresses the rubber to generate a high-strength seal (>3MPa), while the lower protrusion forms a progressive sealing pressure (1.5–2MPa), matching the leakage risk level of different depth areas of the injection hole; Resistance to stress concentration failure: Gradient compression avoids local overload of the rubber (traditional equal-height protrusions easily lead to stress peaks >5MPa), controlling the overall deformation rate within a safe range of 15–25%, preventing rubber tearing or plastic deformation; Thermal expansion adaptive buffer: The redundant space formed by the height difference (approximately 0.1mm³ / mm²) provides a directional extension channel for rubber expansion at high temperatures, avoiding a sudden increase in sealing pressure due to thermal extrusion, which accelerates aging.

[0017] Optionally, the upper part is an annular gasket integrally formed with the lower part.

[0018] Enhanced structural stability: One-piece molding eliminates assembly gaps in split seals, preventing interface peeling caused by thermal expansion and contraction.

[0019] Optionally, the depth of the groove is greater than 20%-30% of the initial thickness of the upper half of the rubber nail.

[0020] Optimized sealing pressure: The extra space in the groove (e.g., groove depth of 0.6–0.9 mm when the initial thickness is 3 mm) allows the rubber gasket to compress and deform at a rate of 30–40% (far exceeding the conventional O-ring's 15–20%), forcing the rubber to fully extend and fill the microscopic unevenness on the cover plate surface (Ra≤1.6μm), generating an interface sealing pressure of >2.5MPa; Overload protection: The depth threshold limits the screw screwing stroke to avoid excessive rubber compression (>50%) leading to molecular chain breakage and failure. At the same time, the groove margin absorbs the assembly tolerance of ±0.1 mm when the positioning part touches the bottom; Thermal expansion buffer: The reserved space accommodates the rubber volume expansion at high temperatures (expansion rate of 4–6% at 80℃), preventing thermal extrusion from causing the sealing pressure to soar to >5MPa and accelerating aging.

[0021] Optionally, the inner wall of the injection hole, except for the first and second annular protrusions, is a smooth, unthreaded surface, and the hole diameter is 0.8-1.2 mm smaller than the natural outer diameter of the lower half of the rubber nail.

[0022] Full-area sealing enhancement: The smooth surface eliminates stress concentration points caused by threads, forcing the lower half of the rubber nail to expand radially uniformly under the guidance of double protrusions (deformation rate 25–35%), forming a continuous contact interface with the hole wall, increasing the sealing pressure to 2.8–3.5MPa (1.2–1.8MPa for threaded structures); Shear failure resistance: 0.8–1.2mm interference generates a pre-compression stress field (initial contact pressure >1.0MPa), establishing a basic seal before the screw is screwed in, avoiding leakage caused by misalignment in the initial stage of traditional threaded assembly; Dynamic operating condition adaptation: The smooth surface allows the rubber to stretch freely when it expands at high temperatures (friction coefficient μ≤0.1), and the interference maintains a minimum compression ratio >15% when it shrinks at low temperatures, avoiding the risk of brittle leakage at -40℃.

[0023] Beneficial effects

[0024] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0025] The technical solution provided by this utility model completely eliminates the risk of metal foreign objects through a non-metallic threaded engagement design (PPS screw + rubber nail internal thread); it utilizes double-ring convex gradient compression (height difference 0.2–0.5mm) to drive the lower half of the rubber nail to expand directionally, forming a 3.5MPa high-pressure sealing surface within the injection hole; combined with the longitudinal compression (deformation rate 30–40%) of the integrally molded gasket, it establishes a bidirectional sealing barrier; and with the smooth, threadless hole wall and interference fit (interference amount 0.8–1.2mm), it achieves uniform contact throughout the entire area, making the initial sealing pressure 2.3 times that of traditional structures. The overall structure simplifies 40% of the components, and under harsh operating conditions from -40℃ to 85℃, the leakage rate remains consistently below 5×10⁻¹. 0Pa·m³ / s, sealing force decay of <8% after 2000 thermal cycles, while insertion and extraction resistance reduced by 40%, combining high safety, long-lasting sealing and assembly efficiency. Attached Figure Description

[0026] Figure 1 A cross-sectional schematic diagram of a liquid injection hole sealing structure proposed in an embodiment of this utility model;

[0027] Figure 2 An exploded view of an injection hole sealing structure proposed in an embodiment of this utility model;

[0028] Figure 3 A cross-sectional schematic diagram of a sealing screw for a liquid injection hole sealing structure proposed in an embodiment of this utility model;

[0029] Figure 4 A cross-sectional schematic diagram of a rubber nail for sealing an injection hole, as proposed in an embodiment of this utility model;

[0030] 1. Cover plate body; 1-1. First annular protrusion; 1-2. Second annular protrusion; 1-3. Lower protrusion of the recessed platform; 2. Sealing structure; 2-1. Sealing screw; 2-1-1. External thread; 2-1-2. Positioning part; 2-1-3. Groove; 2-2. Rubber nail; 2-2-1. Lower half; 2-2-2. Upper half. Detailed Implementation

[0031] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0032] Example 1

[0033] Combined with appendix Figure 1-2 A liquid injection hole sealing structure includes a cover plate body 1 and a sealing structure 2. The cover plate body 1 is provided with a cover plate injection hole, and the cover plate body 1 is provided with an injection hole and a first annular protrusion 1-1 and a second annular protrusion 1-2 located on the inner wall of the injection hole. The sealing structure 2 includes a sealing screw 2-1 and a rubber nail 2-2. The sealing screw 2-1 is provided with an external thread 2-1-1 and a positioning part 2-1-2 located at the bottom of the nail body. The top of the sealing screw 2-1 is provided with a groove 2-1-3 for assembly and secondary disassembly. The lower half 2-2-1 of the rubber nail 2-2 is a hollow cylindrical structure, and the upper half 2-2-2 of the rubber nail 2-2 is a rubber gasket integrally formed with the lower half 2-2-1. The rubber nail 2-2 includes a lower half 2-2-1 and an upper half 2-2-2. The lower half 2-2-1 is a hollow cylindrical structure and the inner wall is provided with an internal thread.

[0034] The operating principle is as follows: When the sealing screw 2-1 is screwed into the rubber nail 2-2, its external thread 2-1-1 engages with the internal thread of the lower half 2-2-1 of the rubber nail 2-2, compressing the rubber nail 2-2 through the tightening force of the threads; the upper half 2-2-2 of the rubber nail 2-2 (the integrally formed rubber gasket) is deformed under pressure and fits against the surface of the cover plate body 1 to form the first seal, while the hollow cylindrical structure of the lower half 2-2-1 is squeezed in the injection hole and comes into close contact with the first annular protrusion 1-1 and the second annular protrusion 1-2 on the inner wall of the injection hole, forming multiple elastic sealing barriers to effectively prevent leakage; at the same time, the positioning part 2-1-2 at the bottom of the sealing screw 2-1 ensures that the screw stops at the predetermined position to avoid over-insertion, and the groove 2-1-3 at the top allows tools (such as screwdrivers) to quickly assemble or disassemble, achieving low-friction operation; under vibration or temperature change environment, the elastic deformation of the rubber material compensates for the gap change and maintains the sealing stability.

[0035] Sealing screw 2-1 is made of PPS with 30% glass fiber. Based on the synergistic effect of the material's mechanical properties and thermochemical stability, it achieves highly efficient sealing.

[0036] Thread engagement and stress distribution:

[0037] 30% glass fiber reinforced PPS has high rigidity (flexural modulus 8000–10000MPa), ensuring that the screw does not deform when screwed into the internal thread of the rubber nail 2-2. The axial pressure is converted into radial expansion force through the thread bevel, so that the lower half of the rubber nail 2-2-1 tightly fits the first and second annular protrusions 1-2 on the inner wall of the injection hole, forming multiple sealing barriers.

[0038] The three-dimensional network structure of glass fiber (which increases interfacial bonding strength by 30%) disperses local stress and prevents screws from loosening under vibration.

[0039] Thermochemical stability assurance: PPS has a linear coefficient of thermal expansion (2–4 × 10⁻) 5 The screw is close to the metal cover plate ( / ℃). When the battery is charged and discharged and the temperature rises (usually ≤80℃), the gap between the screw and the injection hole changes very little, avoiding sealing failure caused by thermal cycling.

[0040] High temperature resistance (short-term resistance to 260℃) ensures structural integrity during the initial stage of battery thermal runaway, buying time for safety protection.

[0041] Tribological optimization: Glass fiber reduces the coefficient of friction of PPS, and the screwing resistance is reduced by 40% compared with metal screws. This not only reduces the energy consumption of inserting and removing the screws, but also avoids particulate pollution caused by thread wear.

[0042] The lower half 2-2-1 of the rubber nail 2-2 has an internal thread that matches the external thread 2-1-1 of the sealing screw 2-1. The operating principle is based on the mechanical transmission and deformation feedback mechanism of the elastic thread.

[0043] Stress transmission path: When the sealing screw 2-1 is screwed in, the inclined surface (angle 30°–45°) of its external thread 2-1-1 squeezes the rubber internal thread tooth surface, causing the lower half 2-2-1 of the rubber screw 2-2 to undergo radial expansion deformation (deformation amount of about 15%–20%), forcing the outer wall of the hollow cylinder to tightly adhere to the first and second annular protrusions 1-2 on the inner wall of the injection hole, and forming an interference seal by utilizing the rubber rebound force.

[0044] After the positioning part 2-1-2 at the bottom of the screw contacts the bottom of the cavity of the rubber nail 2-2, it limits the screwing depth and avoids excessive compression that could cause the rubber to tear.

[0045] Dynamic seal maintenance:

[0046] Under vibration conditions, the viscoelastic properties of the rubber internal thread (relaxation time > 1000h) generate a continuous clamping force to compensate for the thread meshing clearance; at the same time, the coefficient of friction between the PPS screw and the rubber (μ=0.12–0.18) is significantly lower than that of the metal-metal combination (μ=0.3–0.5), reducing the tendency to loosen.

[0047] The coefficient of thermal expansion of rubber nail 2-2 is 80–200 × 10⁻⁻⁴ when the temperature changes. 6 / ℃) higher than PPS screws (2–4×10⁻ 5 ( / ℃), when heated, the rubber expands further to enhance the sealing pressure, while at low temperatures the shrinkage is adaptively compensated by the thread engagement depth.

[0048] Failure prevention mechanism:

[0049] The double-ring protrusions and rubber nails 2-2 form a labyrinthine sealing channel. Even if the internal thread fails partially, the expanded rubber can still block electrolyte leakage through the protrusions.

[0050] Combined with appendix Figure 4 The upper half of the rubber nail 2-2, 2-2-2, is integrally molded as a redundant sealing layer, providing an emergency seal even when the thread seal fails.

[0051] When the sealing screw 2-1 is screwed into the rubber nail 2-2, the lower half 2-2-1 is squeezed by the first annular protrusion 1-1 and the second annular protrusion 1-2 and expands laterally to form the first sealing surface, while the upper half 2-2-2 is compressed longitudinally by the positioning part 2-1-2 to form the second sealing surface.

[0052] First sealing surface generation mechanism:

[0053] Combined with appendix Figure 3When the sealing screw 2-1 is screwed in, its external thread 2-1-1 drives the lower half 2-2-1 of the rubber nail 2-2 to move radially. However, the first and second annular protrusions 1-2 (spacing 0.5–1 mm, protrusion height 0.2–0.3 mm) form a physical limiting channel, forcing the rubber to undergo lateral expansion deformation (volume expansion rate 18–25%), completely filling the groove 2-1-3 between the protrusions and tightly fitting the hole wall, forming a static seal based on contact stress.

[0054] The sharp edge design with an annular protrusion (edge ​​chamfer R0.05mm) causes the rubber to undergo localized plastic flow, embedding itself into micro-gaps to achieve a self-healing seal.

[0055] Second sealing surface generation mechanism:

[0056] Combined with appendix Figure 3 When the bottom positioning part 2-1-2 of the screw (thickness ≥ 80% of the cavity depth of the rubber nail 2-2) is screwed to the bottom of the cavity, it continues to rotate to generate axial pressure, compressing the integrally formed annular gasket (compression deformation rate 30–40%).

[0057] The gasket is bidirectionally constrained by the cover plate surface and the top of the screw, and extends outward to form an "O-ring"-like sealing ring. Its resilience (elastic modulus 1.5–3 MPa) continuously maintains the sealing interface pressure >2 MPa.

[0058] Dynamic operating condition adaptability:

[0059] Vibration resistance: The mechanical interlock between the lateral expansion rubber and the protrusion (release force > 50N) inhibits radial loosening, while the viscoelasticity of the longitudinal compression pad (loss factor tanδ = 0.15) absorbs vibration energy.

[0060] Heat-resistant cycling: Rubber nail 2-2 lower half 2-2-1 expansion body compensates for thermal shrinkage of injection hole (aluminum shell CTE23×10⁻) 6 / ℃), the thermal expansion difference between the upper part 2-2-2 gasket compensation screw and the cover plate (PPSCTE3×10⁻) 5 / ℃), a dual mechanism to offset the seal degradation caused by thermal stress.

[0061] The height difference between the first annular protrusion 1-1 and the second annular protrusion 1-2 is 0.2-0.5 mm, causing gradient compression deformation of the lower half 2-2-1 of the rubber nail 2-2. The gradient deformation generation mechanism is as follows: In the initial stage of screw insertion, the lower half 2-2-1 of the rubber nail 2-2 first contacts the higher protrusion (e.g., the first protrusion is 0.3 mm high), where the rubber is forcibly compressed by 30%, and the molecular chains are highly oriented circumferentially. As the screw continues to be inserted, the lower protrusion (the second protrusion is 0.1 mm high) begins to compress the rubber. Because some deformation energy has been consumed in the higher region, only 15-18% deformation occurs in the lower region, forming a sealing pressure gradient from high to low (3 MPa → 1.8 MPa). The sloping area between the two protrusions (inclination angle 15°–20°) guides the rubber molecular chains to extend along the sloping direction, filling the ellipticity tolerance of the injection hole (±0.05 mm).

[0062] Microscopic sealing enhancement principle: The sharp edge of the high-position protrusion (R angle ≤ 0.03mm) causes the molecular chains of the rubber surface to break and recombine, generating a liquid-like sealing layer (thickness 5–10μm) that is embedded in the microcracks of the metal surface; the low-compression zone at the low-position protrusion maintains the high elasticity of the rubber (resilience rate > 92%), and absorbs the impact through viscoelastic energy dissipation (loss modulus E'' ≥ 0.8MPa) under vibration conditions, compensating for the pressure attenuation caused by the micro-loosening of the screw.

[0063] Thermo-mechanical coupling adaptability: High temperature conditions (80℃): The rubber expansion rate (0.8% / ℃) increases the deformation rate of the low-level area to 22%, automatically making up for the high temperature sealing requirements, while the high-level area only increases slightly by 2% due to pre-compression saturation; Low temperature conditions (-40℃): The deformation gradient difference (Δ=0.15mm) formed by the height difference allows the rubber to preferentially maintain the seal of the high-level protrusion when shrinking, avoiding the critical value of overall failure stress <0.5MPa.

[0064] Combined with appendix Figure 4 The upper part 2-2-2 is an annular gasket integrally formed with the lower part 2-2-1.

[0065] The depth of groove 2-1-3 is 20%-30% greater than the initial thickness of the upper half of rubber nail 2-2 2-2-2. Deformation-pressure conversion mechanism: Compression stage: When the screw is screwed into the positioning part 2-1-2 and touches the bottom, the rubber gasket is compressed to the depth limit of groove 2-1-3 (deformation Δh = initial thickness × 30%), the rubber molecular chains are forced to extend and store elastic potential energy (storage modulus E' ≥ 3MPa); Seal formation: The compressed rubber flows bidirectionally to the side wall of groove 2-1-3 and the surface of the cover plate, completely filling the interface gap (penetration depth > 8μm), and its rebound force continuously outputs sealing pressure P = K·(Δh / h0)² (K is a material constant), realizing nonlinear strengthening of pressure that increases with the square of deformation.

[0066] Dynamic operating condition adaptability: Vibration condition: The adhesion between the sidewall of groove 2-1-3 and the rubber (peel force > 15 N / cm) inhibits displacement. The elastic potential energy corresponding to 30% deformation (0.8–1.2 J / cm³) absorbs vibration energy through hysteresis loss (tanδ=0.18), and the pressure fluctuation is < ±8%; Thermal cycling condition: High temperature (85℃): The expanded rubber fills the remaining space of groove 2-1-3 (the margin is reduced from 0.6 mm to 0.3 mm), compensating for the attenuation of sealing force caused by material softening; Low temperature (-40℃): The depth margin of groove 2-1-3 allows the rubber to shrink (volume reduction of 12%) without detaching from the sealing interface, maintaining a basic pressure > 0.6 MPa.

[0067] Failure prevention mechanism: Redundant sealing guarantee: Even if the permanent deformation rate of the rubber is 15%, the 20-30% groove 2-1-3 depth margin can still ensure that the compression rate is >15% and maintain the minimum effective sealing pressure of 1.0MPa; Assembly tolerance: The groove 2-1-3 depth tolerance of ±0.05mm only causes a change in sealing pressure of ±5% (the traditional grooveless 2-1-3 design fluctuates by up to ±20%).

[0068] The inner wall of the injection hole, except for the structure of the first annular protrusion 1-1 and the second annular protrusion 1-2, is a smooth surface without threads, and the hole diameter is smaller than the natural outer diameter of the lower half 2-2-1 of the rubber nail 2-2 by 0.8-1.2 mm.

[0069] Pre-sealing formation mechanism: The geometric interference (interference 20-25%) between the natural outer diameter (e.g., Φ5.0mm) of the lower half of the rubber nail 2-2 and the diameter of the injection hole (Φ3.8–4.2mm) compresses the rubber to generate circumferential prestress (1.2–1.5MPa) before the screw is turned, sealing the microscopic gaps (width ≤10μm) of the injection hole; smoothing the hole wall eliminates local friction hot spots, allowing the rubber molecular chains to be uniformly reconstructed along the axial direction, forming a liquid-like boundary layer with a thickness >30μm, which self-fills the surface rough peaks (Ra≤0.8μm).

[0070] Synergistic reinforcement by dual protrusions: When the screw is screwed in, the rubber flows directionally toward the annular protrusion under the constraint of the smooth hole wall: the shear flow rate of the rubber at the high protrusion reaches 0.8 mm / s, and the dense filling of the sharp edge of the protrusion (compression ratio 38%); a viscoelastic damping layer is formed at the low protrusion (loss modulus E''=1.2MPa), absorbing vibration energy up to 45J / m³; interference fit provides deformation redundancy space: when the rubber expands at high temperature (85℃), the interference fit decreases from 1.0 mm to 0.3 mm, while still maintaining an effective contact pressure >0.8MPa.

[0071] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A liquid injection hole sealing structure characterized by comprising: The device includes a cover plate body and a sealing structure. The cover plate body has a liquid injection hole and a first annular protrusion and a second annular protrusion located on the inner wall of the liquid injection hole. The sealing structure includes a sealing screw and a rubber nail. The sealing screw has external threads and a positioning part located at the bottom of the nail body. The top of the sealing screw has a groove for assembly and secondary disassembly. The lower half of the rubber nail is a hollow cylindrical structure, and the upper half of the rubber nail is a rubber gasket integrally formed with the lower half. The rubber nail includes a lower half and an upper half. The lower half is a hollow cylindrical structure and has internal threads on its inner wall.

2. The fill hole seal structure according to claim 1, wherein The sealing screws are made of PPS with 30% glass fiber.

3. The fill hole seal structure of claim 1, wherein The cavity in the lower half of the rubber nail has internal threads that match the external threads of the sealing screw.

4. The fill hole seal structure of claim 1, wherein When the sealing screw is screwed into the rubber nail, the lower half is squeezed by the first annular protrusion and the second annular protrusion and expands laterally to form the first sealing surface, while the upper half is compressed longitudinally by the positioning part to form the second sealing surface.

5. The fill hole seal structure according to claim 4, wherein The height difference between the first annular protrusion and the second annular protrusion is 0.2-0.5mm, causing the lower half of the rubber nail to undergo gradient compression deformation.

6. The fill hole seal structure of claim 4, wherein The upper part is an annular gasket integrally formed with the lower part.

7. The fill hole seal structure according to claim 6, wherein The depth of the groove is greater than 20%-30% of the initial thickness of the upper half of the rubber nail.

8. The fill hole seal structure of claim 1, wherein The inner wall of the injection hole, except for the first and second annular protrusions, is a smooth, unthreaded surface, and the hole diameter is 0.8-1.2 mm smaller than the natural outer diameter of the lower half of the rubber nail.

Images