Sealing structure of filter shell and anti-glue-overflow welding method

Abstract

The invention discloses a sealing structure of a filter shell and an anti-glue-overflow welding method, and relates to the technical field of sealing. The sealing structure comprises an upper shell and a lower shell; the welding edge of the upper shell extends downwards to form a circle of annular first welding wall, and a circle of limiting convex ribs protruding inwards are machined on the inner side of the tail end of the first welding wall. The welding edge of the lower shell extends upwards to form a circle of second welding wall matched with the first welding wall, and a circle of sealing groove with the section shape matched with the limiting convex rib is machined in the outer side of the top end of the second welding wall. Through the closed annular overflowing glue containing cavity defined by the limiting convex rib, the sealing groove and the first welding wall and in combination with the annular flow guide groove in the groove bottom of the sealing groove, overflowing glue generated in the welding process can be fully contained, the situation that the overflowing glue overflows to a filter material area is avoided, the filtering efficiency and the dust containing capacity of the filter are guaranteed, and the service life of a product is prolonged.

Description

Technical Field

[0001] This invention relates to the field of sealing technology, and in particular to a sealing structure for a filter housing and a method for preventing adhesive spillage during welding. Background Technology

[0002] The air filter is a key component of the air intake system. Its core function is to filter impurities in the air, ensuring that the air entering the system is clean. The upper and lower housings of the filter are usually sealed together using processes such as hot plate welding, ultrasonic welding, and laser welding to ensure the airtightness of the entire filter assembly and prevent unfiltered air from short-circuiting.

[0003] Currently, most common welded sealing structures are simple planar butt joints or single-layer boss butt joints. These traditional structures have the following significant drawbacks: 1. Excess adhesive is difficult to avoid: During the welding process, the molten plastic (excess adhesive) will overflow from the weld surface due to pressure and high temperature. This excess adhesive can easily flow into the filter, directly clogging or contaminating the filter media, leading to an increase in the filter's initial pressure differential, a decrease in filtration efficiency, a reduction in dust holding capacity, and a serious shortening of the product's service life.

[0004] 2. Poor sealing stability: The simple butt joint structure has limited welding area and strength. When faced with vibration and temperature changes in the intake system, the weld line may crack, leading to seal failure.

[0005] 3. High requirements for process control: In order to minimize glue overflow, it is often necessary to control welding parameters (such as time, temperature and pressure) with extreme precision, which places higher demands on production equipment and processes, and increases production costs and quality control difficulty.

[0006] Therefore, there is an urgent need in this field for a new sealing structure design that can ensure both the strength of the weld and the reliability of the seal, while fundamentally solving the problem of adhesive overflow contaminating the filter material. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the present invention provides a sealing structure for a filter housing and a method for preventing adhesive overflow during welding. The technical solution is as follows: A sealing structure for a filter housing, the sealing structure comprising an upper housing and a lower housing; The welding edge of the upper shell extends downward to form a ring-shaped first welding wall, and a ring of inwardly protruding limiting ribs is processed on the inner side of the end of the first welding wall. The welding edge of the lower shell extends upward to form a second welding wall that matches the first welding wall. A sealing groove with a cross-sectional shape that matches the limiting rib is machined on the outer side of the top of the second welding wall. When the upper and lower shells are combined, the limiting ribs, the groove wall of the sealing groove, and the inner wall of the first welded wall together form a closed annular overflow cavity sealing structure.

[0008] Optionally, the cross-section of the limiting rib is circular.

[0009] Optionally, the outer diameter of the second welded wall is in clearance fit with the inner diameter of the first welded wall, and the outer diameter of the second welded wall is 0.1-0.2 mm smaller than the inner diameter of the first welded wall.

[0010] Optionally, the depth of the sealing groove is 0.2mm-0.3mm greater than the height of the limiting rib; and the bottom of the sealing groove is provided with an annular guide groove, the width of which is 0.8mm-1mm and the depth is 0.5mm, forming a secondary overflow space to uniformly disperse the overflow.

[0011] Optionally, the thickness of the first welded wall is designed to gradually change along the height direction, wherein the thickness at the top of the first welded wall is 2mm-3mm and the thickness at the end is 3mm-4mm, in order to improve the heat resistance and structural strength during the welding process.

[0012] Optionally, the inner side of the first welded wall is provided with axial reinforcing ribs, the number of which is 4-6, and they are evenly distributed along the circumference of the first welded wall; the height of the axial reinforcing ribs is half of the total height of the first welded wall, which is used to enhance the vibration and deformation resistance of the first welded wall.

[0013] Optionally, the top end face of the second welded wall is provided with a ring-shaped welding fusion groove, the width of which is 1mm-1.2mm and the depth is 0.8mm. The welding fusion groove is used to increase the fusion contact area of ​​the welding surface and improve the welding strength.

[0014] Optionally, the outer surface of the limiting rib is provided with a guide chamfer, the size of which is 0.3mm-0.5mm, which serves as a guide during the assembly of the upper and lower housings; The closed annular overflow cavity has a volume of 8mm³-12mm³ and is used to contain the overflow generated during a single welding process, preventing the overflow from spilling into the filter media area.

[0015] The anti-overflow adhesive welding method for the sealing structure of the filter housing includes the following steps: Step 1: Assembly and positioning. Align the upper and lower housings, and fit the first welded wall onto the outside of the second welded wall until the limiting rib is fully embedded in the sealing groove, ensuring that the overflow cavity is closed. Step 2: Welding and fusion. Using hot plate welding, ultrasonic welding or laser welding, the mating surfaces of the first and second welded walls are heated to melt the plastic at the mating surfaces. At the same time, axial pressure is applied to make the molten plastic fill the gap between the mating surfaces and achieve the fusion connection between the first and second welded walls. Step 3: Excess adhesive containment. The excess adhesive generated during the welding process flows into the closed annular excess adhesive containment cavity under axial pressure and is contained within the containment cavity to prevent it from overflowing outward. Step 4: Cooling and shaping, maintaining axial pressure until the molten plastic cools and solidifies, completing the welding and sealing of the filter housing.

[0016] Optionally, the method for ensuring that the limiting rib is fully embedded in the sealing groove in step 1 is achieved in the following way: The height of the limiting rib is preset to H1 and the depth of the sealing groove is preset to H2, with H2 being 0.2mm-0.3mm larger than H1. At the same time, a first reference line is marked on the top end face of the upper shell and a second reference line is marked on the top end face of the lower shell. The first reference line and the second reference line are staggered when the upper and lower shells are not assembled, and the initial stagger distance between the two reference lines is equal to H2. During assembly and positioning, an axial preload of 0.1MPa-0.15MPa is continuously applied downwards to push the upper housing. The relative position of the first and second baselines is captured by a vision camera. When the vision analysis module determines that the two baselines are completely coincident, and the pressure fluctuation of the axial preload is less than or equal to ±0.01MPa, it is determined that the limiting rib is completely embedded in the sealing groove and the overflow cavity is closed.

[0017] In summary, the present invention has at least one of the following beneficial technical effects: This invention provides a sealing structure for a filter housing and a method for preventing glue overflow during welding. The closed annular glue overflow containment cavity formed by the limiting rib, the sealing groove and the first welding wall, combined with the annular guide groove at the bottom of the sealing groove, can fully contain the glue overflow generated during the welding process, preventing the glue overflow to the filter material area, ensuring the filter efficiency and dust holding capacity of the filter, and extending the product service life.

[0018] The gradual thickness design of the first welded wall along the height direction enhances the heat resistance and structural stability during welding; the axial reinforcing ribs on the inner side of the first welded wall can resist vibration deformation; and the annular welding fusion groove at the top of the second welded wall increases the fusion contact area of ​​the welding surface. Together, they improve the sealing reliability and connection strength of the shell after welding and reduce the risk of weld line cracking.

[0019] The clearance fit between the second welded wall and the first welded wall, and the guide chamfer on the outer surface of the limiting rib, simplify the assembly and alignment process of the upper and lower shells and improve assembly efficiency. In the anti-overflow adhesive welding method, the combination of the baseline and axial preload can accurately determine whether the limiting rib is fully embedded in the sealing groove, ensuring the sealing of the overflow adhesive receiving cavity. The method is compatible with various processes such as hot plate welding, ultrasonic welding, and laser welding, reducing the dependence on high-precision equipment, improving production yield and efficiency, and controlling production costs. Attached Figure Description

[0020] Figure 1 This is a cross-sectional schematic diagram of the sealing structure of a filter housing according to the present invention; Figure 2 This is a three-dimensional structural diagram of a sealing structure for a filter housing according to the present invention; Figure 3 This is a schematic diagram of the upper housing structure of a sealing structure for a filter housing according to the present invention; Figure 4 This is a schematic diagram of the lower housing structure of a sealing structure for a filter housing according to the present invention; Explanation of reference numerals in the attached drawings: 1. Upper shell; 11. First welded wall; 12. Limiting rib; 2. Lower shell; 21. Second welded wall; 22. Sealing groove. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings.

[0022] This invention discloses a sealing structure for a filter housing and a method for preventing adhesive overflow during welding.

[0023] Reference Figures 1-4 Example 1: A sealing structure for a filter housing, the sealing structure comprising an upper housing 1 and a lower housing 2; The welding edge of the upper shell 1 extends downward to form a ring-shaped first welding wall 11, and a ring of inwardly protruding limiting ribs 12 is processed on the inner side of the end of the first welding wall 11. The welding edge of the lower housing 2 extends upward to form a second welding wall 21 that matches the first welding wall. A sealing groove 22 with a cross-sectional shape that matches the limiting rib 12 is processed on the outer side of the top of the second welding wall 21. When the upper shell 1 and the lower shell 2 are combined, the limiting rib 12, the groove wall of the sealing groove 22 and the inner wall of the first welded wall 11 together form a closed annular overflow cavity sealing structure.

[0024] In Example 2, the cross-section of the limiting rib 12 is circular.

[0025] In Example 3, the outer diameter of the second welded wall 21 is in clearance fit with the inner diameter of the first welded wall 11, and the outer diameter of the second welded wall 21 is 0.1-0.2 mm smaller than the inner diameter of the first welded wall 11.

[0026] In Example 4, the depth of the sealing groove 22 is 0.2mm-0.3mm greater than the height of the limiting rib 12; and the bottom of the sealing groove 22 is provided with an annular guide groove, the width of which is 0.8mm-1mm and the depth is 0.5mm, forming a secondary overflow space to uniformly disperse the overflow.

[0027] In Example 5, the thickness of the first welded wall 11 is designed to gradually change along the height direction, wherein the thickness of the top of the first welded wall 11 is 2mm-3mm and the thickness of the bottom is 3mm-4mm, so as to improve the heat resistance and structural strength during the welding process.

[0028] By adopting the above technical solution, the upper shell 1 and the lower shell 2 achieve sealing and anti-overflow functions through the sleeve fit of the welded walls. The core logic is that the structure encloses and forms a dedicated overflow space. The first welded wall 11 of the upper shell 1 extends downward and the second welded wall 21 of the lower shell 2 extends upward. When the two are sleeved, they can form a preliminary annular welding mating surface, providing a basic contact area for welding fusion. At the same time, the limiting rib 12 on the inner side of the end of the first welded wall 11 and the sealing groove 22 on the outer side of the top of the second welded wall 21 are precisely matched. The three together enclose and form a closed annular overflow cavity. This cavity serves as a dedicated storage space for molten plastic (overflow) during the welding process. It can directly block the flow of overflow to the filter media area inside the filter or the external environment, eliminating the problem of overflow contaminating the filter media and affecting the filtration performance from the structural level, while ensuring the airtightness of the shell after welding.

[0029] The limiting rib 12 adopts a circular cross-section, the principle of which is to "optimize assembly compatibility and sealing fit". The circular cross-section has no sharp corners, which can reduce the frictional resistance between the limiting rib 12 and the inner wall of the sealing groove 22 when the upper shell 1 and the lower shell 2 are assembled and connected, reduce the difficulty of assembly alignment and achieve smooth fitting; at the same time, the circular cross-section can form an arc-shaped fitting surface with the inner wall of the sealing groove 22. Compared with the sharp corner cross-section, it can reduce the fitting gap, improve the sealing tightness after the rib and the groove are matched, further enhance the sealing of the overflow cavity, and prevent overflow from leaking from the fitting gap between the rib and the groove.

[0030] The outer diameter of the second welded wall 21 and the inner diameter of the first welded wall 11 are in clearance fit, with the dimensional difference controlled within 0.1-0.2 mm. The principle behind this is to "balance assembly smoothness and fit accuracy." This clearance size avoids both the jamming caused by an excessively small clearance (which requires force and can easily deform the welded wall) and the shaking after assembly caused by an excessively large clearance (which affects welding alignment accuracy). At the same time, the small clearance provides adequate flow space for the molten plastic during welding, ensuring that the molten plastic can fully fill the welding mating surface, improving the integrity of the weld fusion, and thus enhancing the connection strength and sealing reliability of the shell.

[0031] The depth of the sealing groove 22 is 0.2mm-0.3mm greater than the height of the limiting rib 12, and an annular guide groove is provided at the bottom of the groove. The principle is "graded expansion and uniform drainage of overflow adhesive". On the one hand, the groove depth is greater than the height of the rib, which can form a preliminary overflow adhesive buffer space at the bottom of the groove after the rib is fully embedded in the groove, avoiding the rib from directly pressing against the bottom of the groove and causing the overflow adhesive to have nowhere to be contained. On the other hand, the annular guide groove at the bottom of the groove (width 0.8mm-1mm, depth 0.5mm) can evenly disperse the overflow adhesive entering the groove along the circumferential direction, preventing the overflow adhesive from accumulating excessively in local areas (excessive accumulation can easily break through the boundary of the receiving cavity), forming a graded overflow adhesive treatment structure with a main receiving cavity and a guide groove as secondary receiving spaces, which greatly improves the overflow adhesive containing capacity and ensures that the overflow adhesive is completely confined within the groove during the welding process.

[0032] The first welded wall 11 adopts a gradually varying thickness design along the height direction (2mm-3mm at the top and 3mm-4mm at the bottom), the principle of which is to directionally strengthen the performance of key areas. During the welding process, the bottom of the first welded wall 11 is the fusion core area that directly contacts the second welded wall 21 and needs to withstand the high temperature and axial pressure of welding. The larger end thickness (3mm-4mm) can improve the heat resistance of this area, reduce structural deformation at high temperatures, and increase the effective area of ​​welding fusion, thereby strengthening the structural strength after welding. The slightly smaller thickness at the top (2mm-3mm) avoids unnecessary material redundancy while ensuring the overall structural stability of the upper shell 1, achieving a lightweight shell design that balances performance and cost.

[0033] In Example 6, the inner side of the first welded wall 11 is provided with axial reinforcing ribs 111. The number of axial reinforcing ribs 111 is 4-6, and they are evenly distributed along the circumference of the first welded wall 11. The height of the axial reinforcing ribs 111 is half of the total height of the first welded wall 11, which is used to enhance the vibration resistance and deformation resistance of the first welded wall 11.

[0034] In Example 7, the top end face of the second welded wall 21 is provided with a ring-shaped welding fusion groove 212. The width of the welding fusion groove 212 is 1mm-1.2mm and the depth is 0.8mm. The welding fusion groove 212 is used to increase the fusion contact area of ​​the welding surface and improve the welding strength.

[0035] In Example 8, the outer surface of the limiting rib 12 is provided with a guide chamfer, the size of which is 0.3mm-0.5mm, and is used to guide the upper shell 1 and the lower shell 2 during assembly. The closed annular overflow cavity has a volume of 8mm³-12mm³ and is used to contain the overflow generated during a single welding process, preventing the overflow from spilling into the filter media area.

[0036] By adopting the above technical solution, 4-6 axial reinforcing ribs 111 are evenly distributed along the circumference of the first welded wall 11, which can ensure that the force on the first welded wall 11 is evenly transmitted in the circumferential direction, avoiding local stress concentration. The height of the ribs is set to half the total height of the first welded wall 11, which can effectively support the critical stress area of ​​the welded wall (near the welding end), enhancing the overall bending and tensile resistance of the welded wall, while preventing excessive height from affecting the assembly and connection of the upper shell 1 and the lower shell 2. During the operation of the filter, the vibration generated by the intake system will be transmitted to the welding area through the shell. The axial reinforcing ribs 111 can offset some of the vibration energy, preventing the first welded wall 11 from deforming due to long-term vibration, thereby avoiding weld line cracking or seal failure of the overflow cavity, and ensuring the long-term stability of the sealing structure.

[0037] During welding, the molten plastic needs to achieve intermolecular bonding through sufficient contact. The annular welding fusion groove 212, with a width of 1mm-1.2mm and a depth of 0.8mm, can create an additional fusion space within the groove on top of the traditional planar butt welding. The molten plastic can not only fill the gap between the weld wall end faces but also flow into the fusion groove, forming a dual bonding structure of "end face fusion + groove fusion," significantly increasing the fusion contact area. This size range has been verified by the process to ensure that the molten plastic can completely fill the groove (avoiding residual voids in the groove that could lead to sealing defects) without the groove being too large, resulting in insufficient molten material and affecting the fusion effect. Ultimately, this improves the connection strength of the upper and lower shells after welding and reduces the risk of cracking in the welded area.

[0038] When the upper and lower housings are assembled and connected, the transition slope formed by the guide chamfer reduces the initial contact friction resistance between the limiting rib 12 and the inner wall of the sealing groove 22, allowing the rib to slide smoothly into the groove along the chamfered slope. This avoids hard jamming caused by misalignment between the rib and the groove, reducing the risk of structural damage during assembly. The 0.3mm-0.5mm chamfer size is designed to be balanced, ensuring sufficient guiding effect without weakening the structural strength of the limiting rib 12 due to excessive chamfer, thus ensuring a good sealing fit after the rib and groove are engaged.

[0039] Through tests on the amount of adhesive overflow generated by mainstream processes such as hot plate welding, ultrasonic welding, and laser welding, the volume of adhesive overflow generated in a single welding operation is typically in the range of 5mm³-10mm³. A volume of 8mm³-12mm³ can completely cover this range, ensuring that all excess molten plastic generated during welding is confined within the containment cavity and does not overflow into the filter media area due to insufficient volume. Simultaneously, this volume setting avoids material waste caused by an excessively large containment cavity, achieving a lightweight structure while maintaining the anti-overflow effect.

[0040] Example 9, a method for preventing overflow adhesive welding based on the sealing structure of the filter housing. The welding method includes the following steps: Step 1: Assembly and positioning. Align the upper housing 1 with the lower housing 2, so that the first welded wall 11 is fitted onto the outside of the second welded wall 21 until the limiting rib 12 is completely embedded in the sealing groove 22, ensuring that the overflow cavity is closed. Step 2: Welding and fusion. Using hot plate welding, ultrasonic welding or laser welding, the mating surfaces of the first welding wall 11 and the second welding wall 21 are heated to melt the plastic at the mating surfaces. At the same time, axial pressure is applied to make the molten plastic fill the mating gap and achieve the fusion connection between the first welding wall 11 and the second welding wall 21. Step 3: Excess adhesive containment. The excess adhesive generated during the welding process flows into the closed annular excess adhesive containment cavity under axial pressure and is contained within the containment cavity to prevent it from overflowing outward. Step 4: Cooling and shaping, maintaining axial pressure until the molten plastic cools and solidifies, completing the welding and sealing of the filter housing.

[0041] In Example 10, the method for ensuring that the limiting rib 12 is completely embedded in the sealing groove 22 in step 1 is achieved in the following way: The height of the limiting rib 12 is set to H1 and the depth of the sealing groove 22 is set to H2, with H2 being 0.2mm-0.3mm larger than H1. At the same time, a first reference line is marked on the top end face of the upper shell 1 and a second reference line is marked on the top end face of the lower shell 2. The first reference line and the second reference line are staggered when the upper and lower shells are not assembled, and the initial stagger distance between the two reference lines is equal to H2. During assembly and positioning, an axial preload of 0.1MPa-0.15MPa is continuously applied downwards to push the upper housing 1. The relative position of the first reference line and the second reference line is captured by a vision camera. When the vision analysis module determines that the two reference lines are completely coincident, and the pressure fluctuation of the axial preload is less than or equal to ±0.01MPa, it is determined that the limiting rib 12 is completely embedded in the sealing groove 22 and the overflow cavity is closed.

[0042] By adopting the above technical solution, by fitting the first welding wall 11 onto the outside of the second welding wall 21, the limiting rib 12 is fully embedded in the sealing groove 22. Essentially, this utilizes the matching structure of the two to construct a complete closed annular overflow cavity: only when the rib is fully embedded in the groove can the cavity be guaranteed to be gapless, laying a structural foundation for limiting overflow during subsequent welding and avoiding leakage and overflow of adhesive due to improper assembly.

[0043] The use of hot plate welding, ultrasonic welding, or laser welding processes is an appropriate choice based on the melting characteristics of plastic and the design of the welded wall structure. All three processes can precisely heat the mating surfaces of the first welded wall 11 and the second welded wall 21, bringing the plastic to a molten state. Simultaneously, axial pressure is applied, which on the one hand promotes the molten plastic to fully fill the gap between the welded walls, achieving molecular-level fusion and ensuring the overall airtightness of the shell; on the other hand, it provides the power for the subsequent overflow of adhesive into the receiving cavity, ensuring that fusion and overflow guidance occur simultaneously.

[0044] Under axial pressure, the overflow adhesive generated during welding will naturally flow to the space with less resistance. The closed annular overflow adhesive receiving cavity serves as a pre-designed exclusive space, providing the only area where the overflow adhesive can flow. At the same time, the structural boundaries of the receiving cavity (limiting rib 12, sealing groove 22 groove wall, and inner wall of the first welded wall 11) can effectively prevent the overflow adhesive from spreading to the filter material area or the external environment, thus achieving complete control over the overflow adhesive.

[0045] The molten plastic is cooled under pressure, which ensures a stable bond between the fusion interface of the first welded wall 11 and the second welded wall 21. At the same time, it ensures that the fit between the limiting rib 12 and the sealing groove 22 remains unchanged, avoiding cracking of the cavity gap or weld line due to cooling contraction, and ultimately forming a stable sealed welded structure.

[0046] The depth H2 of the pre-set sealing groove 22 is 0.2mm-0.3mm larger than the height H1 of the limiting rib 12. Essentially, this provides sufficient embedding space for the limiting rib 12. This avoids the rib from not being able to be fully embedded due to H2 being too small (resulting in tightness and jamming), and ensures that the rib fits tightly against the inner wall of the groove after being embedded through a slight dimensional difference, thus providing a structural prerequisite for sealing the overflow cavity.

[0047] A first baseline is marked on the top end face of the upper housing 1, and a second baseline is marked on the top end face of the lower housing 2, with an initial offset distance equal to H2. The principle is to transform the embedding relationship between the rib and the groove into an intuitive visual positional relationship. Since the offset distance of the baselines is consistent with the groove depth, when the two baselines completely coincide, it can directly reflect that the descent distance of the upper housing 1 relative to the lower housing 2 is exactly equal to H2, corresponding to the limit rib 12 completely entering the sealing groove 22, realizing the visual judgment of the embedding state.

[0048] The continuous application of axial preload of 0.1MPa-0.15MPa is to ensure that the rib can slide smoothly into the groove during assembly and avoid positional deviation due to assembly resistance. The pressure fluctuation range of less than or equal to ±0.01MPa is the physical feedback of the rib being fully embedded in the groove: when the rib is not fully embedded, it will generate irregular friction with the inner wall of the groove, resulting in large pressure fluctuations; when the rib is fully embedded, the rib fits stably with the inner wall of the groove, there is no additional resistance, and the pressure tends to be stable.

[0049] Dual Judgment Principle: Combining the visual camera to determine baseline alignment and pressure fluctuation stability, this principle uses dual verification of visual position and physical state to avoid errors from a single judgment. Baseline alignment alone might result in incomplete fitting of the rib to the inner wall of the groove due to assembly tilt, while pressure stability alone might lead to misjudgment due to other structural obstructions. Combining both methods accurately confirms that the limiting rib 12 is fully embedded in the sealing groove 22, ensuring the overflow adhesive receiving cavity is sealed.

[0050] The following specific implementation examples illustrate the implementation principle of this invention: To address the welding and sealing requirements of the upper and lower housings of an air filter, a specific filter housing sealing structure and a matching anti-overflow adhesive welding method are provided. The parameters of each component and the process parameters are determined based on the aforementioned technical solution, as detailed below: Specific parameters of filter housing sealing structure Basic components and materials: Both the upper shell 1 and the lower shell 2 are made of modified PP material containing 12% glass fiber, which can improve the structural stability and temperature resistance after welding. The welded edge of the upper shell 1 extends downward to form an annular first welded wall 11. The total height of the first welded wall 11 is 8mm, and its thickness is gradually designed along the height direction: the thickness at the top is 2.5mm and the thickness at the end is 3.5mm. The inner diameter of the first welded wall 11 is set to 20mm, and five axial reinforcing ribs 111 are evenly distributed on the inner side. The height of the axial reinforcing ribs 111 is 4mm (that is, half the total height of the first welded wall 11), and the cross-section is rectangular (width 1.5mm, thickness 1mm), which is used to enhance the vibration deformation resistance of the first welded wall 11.

[0051] The lower shell 2 has an upward-extending welded edge to form an annular second welded wall 21. The outer diameter of the second welded wall 21 is 19.85 mm (0.15 mm smaller than the inner diameter of the first welded wall 11), achieving a clearance fit between the two. The end face of the top of the second welded wall 21 is provided with an annular welding fusion groove 212. The width of the welding fusion groove 212 is 1.1 mm and the depth is 0.8 mm, which is used to increase the welding fusion contact area.

[0052] Limiting ribs and sealing groove structure: The inner side of the end of the first welded wall 11 is machined with a ring of inwardly protruding limiting ribs 12. The cross-section of the limiting ribs 12 is circular, with a diameter (i.e., height H1) of 1.2 mm and a 0.4 mm guide chamfer on the outer surface to reduce the difficulty of assembly alignment.

[0053] A sealing groove 22 is machined on the outer side of the top of the second welded wall 21. The cross section of the sealing groove 22 is adapted to the limiting rib 12, and the depth H2 is 1.4mm (0.2mm larger than H1). A ring-shaped guide groove is provided at the bottom of the sealing groove 22. The width of the ring-shaped guide groove is 0.9mm and the depth is 0.5mm, forming a secondary overflow adhesive receiving space.

[0054] When the upper shell 1 and the lower shell 2 are combined, the limiting rib 12, the groove wall of the sealing groove 22 and the inner wall of the first welding wall 11 together form a closed annular overflow cavity. The volume of the cavity is calculated to be 10 mm³, which can completely accommodate the overflow generated by a single welding.

[0055] Specific steps for anti-overflow adhesive welding method: Step 1: Assembly and Positioning. First reference line is marked on the top end face of the upper housing 1 using laser, and second reference line is marked on the top end face of the lower housing 2. Before assembly, the initial offset distance between the two reference lines is 1.4mm (i.e., the depth H2 of the sealing groove 22). The upper housing 1 and lower housing 2 are aligned, with the first welded wall 11 fitting onto the outside of the second welded wall 21. An axial preload of 0.12MPa is continuously applied downwards using the assembly equipment to push the upper housing 1. Simultaneously, a 10-megapixel visual camera captures the relative position of the two reference lines. The visual analysis module identifies the positional relationship in real time. When the two reference lines are determined to be completely aligned, the axial preload fluctuation amplitude is monitored synchronously by a pressure sensor. If the fluctuation amplitude is stable within ±0.01MPa, it can be confirmed that the limiting rib 12 is completely embedded in the sealing groove 22, and the overflow cavity is closed.

[0056] Step 2: Welding Fusion In this embodiment, a hot plate welding process is selected. The heating plate of the welding equipment first preheats the mating surface of the first welding wall 11 and the second welding wall 21 at a temperature of 230°C for 4 seconds. Then, the temperature of the heating plate is raised to 260°C to melt and heat the mating surface for 10 seconds. At the same time, an axial pressure of 0.4 MPa is applied to make the molten plastic fully fill the gap between the welding walls and the annular welding fusion groove 212 of the second welding wall 21, so as to achieve molecular-level fusion connection between the first welding wall 11 and the second welding wall 21.

[0057] Step 3: The overflow adhesive generated during the welding process (approximately 8 mm³ in volume) flows naturally into the closed annular overflow adhesive receiving cavity under the action of 0.4 MPa axial pressure. Some of the overflow adhesive further enters the annular guide groove at the bottom of the sealing groove 22, and is evenly dispersed along the circumference, completely confined within the receiving cavity, with no overflow.

[0058] Step 4: Cooling and Shaping. Maintaining an axial pressure of 0.4 MPa, the welding area is cooled using air-cooling equipment (wind speed 2.5 m / s) for 35 seconds until the molten plastic is completely cooled and solidified. Then, the axial pressure is removed to complete the welding and sealing of the filter housing.

[0059] Testing revealed that the filter housing manufactured using the sealing structure and welding method of this embodiment has a tensile strength of 18 MPa in the welded area, meets the leakage requirement of less than or equal to 5 kPa / min in terms of airtightness, and the filter material is free of any overflow adhesive contamination. The filtration efficiency remains above 99.5%, and the dust holding capacity meets the industry's first-class standard.

[0060] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A sealing structure for a filter housing, characterized in that: The sealing structure includes an upper housing (1) and a lower housing (2); The welding edge of the upper shell (1) extends downward to form a ring-shaped first welding wall (11), and a ring of inwardly protruding limiting ribs (12) is processed on the inner side of the end of the first welding wall (11). The welding edge of the lower shell (2) extends upward to form a second welding wall (21) that matches the first welding wall. A sealing groove (22) with a cross-sectional shape that matches the limiting rib (12) is processed on the outer side of the top of the second welding wall (21). When the upper shell (1) and the lower shell (2) are combined, the limiting rib (12), the groove wall of the sealing groove (22) and the inner wall of the first welded wall (11) together form a closed annular overflow cavity sealing structure.

2. The sealing structure of a filter housing according to claim 1, characterized in that: The cross-section of the limiting rib (12) is circular.

3. The sealing structure of a filter housing according to claim 1, characterized in that: The outer diameter of the second welded wall (21) is in clearance fit with the inner diameter of the first welded wall (11), and the outer diameter of the second welded wall (21) is 0.1-0.2 mm smaller than the inner diameter of the first welded wall (11).

4. The sealing structure of a filter housing according to claim 3, characterized in that: The depth of the sealing groove (22) is 0.2mm-0.3mm greater than the height of the limiting rib (12); and the bottom of the sealing groove (22) is provided with an annular guide groove, the width of which is 0.8mm-1mm and the depth is 0.5mm, forming a secondary overflow space to uniformly disperse the overflow.

5. The sealing structure of a filter housing according to claim 4, characterized in that: The thickness of the first welded wall (11) is gradually designed along the height direction, wherein the thickness of the top of the first welded wall (11) is 2mm-3mm and the thickness of the bottom is 3mm-4mm, so as to improve the heat resistance and structural strength during the welding process.

6. The sealing structure of a filter housing according to claim 4, characterized in that: The inner side of the first welded wall (11) is provided with axial reinforcing ribs (111). The number of axial reinforcing ribs (111) is 4-6, and they are evenly distributed along the circumference of the first welded wall (11). The height of the axial reinforcing ribs (111) is half of the total height of the first welded wall (11), which is used to enhance the vibration resistance and deformation resistance of the first welded wall (11).

7. The sealing structure of a filter housing according to claim 6, characterized in that: The end face of the top of the second weld wall (21) is provided with a ring-shaped welding fusion groove (212). The width of the welding fusion groove (212) is 1mm-1.2mm and the depth is 0.8mm. The welding fusion groove (212) is used to increase the fusion contact area of ​​the welding surface and improve the welding strength.

8. The sealing structure of a filter housing according to claim 7, characterized in that: The outer surface of the limiting rib (12) is provided with a guide chamfer, the size of which is 0.3mm-0.5mm, and is used to guide the upper shell (1) and the lower shell (2) during assembly. The closed annular overflow cavity has a volume of 8mm³-12mm³ and is used to contain the overflow generated during a single welding process, preventing the overflow from spilling into the filter media area.

9. A method for preventing overflow adhesive welding based on the sealing structure of the filter housing according to claim 8, characterized in that: The welding method includes the following steps: Step 1: Assembly and positioning. Align the upper shell (1) with the lower shell (2) so that the first welded wall (11) fits onto the outside of the second welded wall (21) until the limiting rib (12) is completely embedded in the sealing groove (22) to ensure that the overflow cavity is closed. Step 2: Welding and fusion. Using hot plate welding, ultrasonic welding or laser welding, the mating surfaces of the first welding wall (11) and the second welding wall (21) are heated to melt the plastic at the mating surfaces. At the same time, axial pressure is applied to make the molten plastic fill the mating gap and achieve the fusion connection between the first welding wall (11) and the second welding wall (21). Step 3: Excess adhesive containment. The excess adhesive generated during the welding process flows into the closed annular excess adhesive containment cavity under axial pressure and is contained within the containment cavity to prevent it from overflowing outward. Step 4: Cooling and shaping, maintaining axial pressure until the molten plastic cools and solidifies, completing the welding and sealing of the filter housing.

10. A method for preventing overflow adhesive welding based on the sealing structure of the filter housing according to claim 9, characterized in that: The method for ensuring that the limiting rib (12) is fully embedded in the sealing groove (22) in step 1 is achieved in the following way: The height dimension of the limiting rib (12) is set to H (1) and the depth dimension of the sealing groove (22) is set to H2, and H2 is 0.2mm-0.3mm larger than H1; at the same time, the first reference line is marked on the top end face of the upper shell (1) and the second reference line is marked on the top end face of the lower shell (2). The first reference line and the second reference line are staggered when the upper and lower shells are not assembled, and the initial stagger distance between the two reference lines is equal to H2. During assembly and positioning, an axial preload of 0.1MPa-0.15MPa is continuously applied downward to push the upper housing (1). The relative position of the first baseline and the second baseline is captured by a vision camera. When the vision analysis module determines that the two baselines are completely coincident, the pressure fluctuation of the axial preload is less than or equal to ±0.01MPa. It is determined that the limiting rib (12) is completely embedded in the sealing groove (22) and the overflow cavity is closed.

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