A sealing structure for 3D printing micro-powder spiral conveying

Abstract

The utility model provides a kind of sealing structure for 3D printing micro powder spiral conveying, including shell, conveying shaft and annular sealing flange.Sealing flange inside is equipped with sealing chamber, multiple sealing rings are arranged in the chamber along the axial direction, and its inner and outer wall is respectively attached with sealing chamber and rotating shaft.Rigid connection gland is on rotating shaft, and zigzag labyrinth passage is formed between gland and flange, inlet is connected to shell and is equipped with felt dustproof ring, and outlet extends to sealing chamber.Bearing is arranged in the rear side of sealing chamber.The structure is designed by dust ring, labyrinth passage, multiple alternating sealing ring and constitutes ladder type sealing and discharging, effectively prevents micro powder from invading bearing, solves the problem of bearing failure due to powder wear, significantly improves equipment stability and service life.

Description

Technical Field

[0001] This utility model relates to the field of 3D printing micro powder spiral conveying technology, and more specifically, to a sealing structure for 3D printing micro powder spiral conveying. Background Technology

[0002] In 3D printing powder conveying systems, screw conveyors are widely used for transporting materials such as metal powders and ceramic powders due to their stable continuous feeding and high control precision. However, in actual operation, seal failure on the conveyor side has become a key issue restricting the stability and service life of the equipment.

[0003] In the current mainstream screw conveyor structure, due to the fine particle size of 3D printing powder, the powder is easy to penetrate through the sealing gap under the influence of gravity and other factors. The powder will continuously invade the sealed cavity and then come into contact with the bearing assembly at the end of the conveyor shaft.

[0004] As the core component supporting the rotation of the conveyor shaft, the bearing's raceway and ball bearings are extremely sensitive to impurities due to their precise fit. When powder enters the bearing, it not only disrupts the stability of the lubricating grease but also causes abrasive wear during high-speed operation, leading to increased bearing clearance, intensified vibration, and ultimately a chain reaction of failures such as conveyor shaft eccentricity and rubbing between the helical blades and the cylinder wall. This not only increases equipment maintenance costs but also severely impacts the continuity and precision of 3D printing production due to frequent downtime for repairs. In other words, the bearing failure problem under gravity and fine powder conditions has not yet been effectively solved. Utility Model Content

[0005] This application aims to solve the technical problem of wear caused by micropowder intrusion into bearings. To overcome the defects of the prior art, this application provides a sealing structure for spiral conveying of micropowder in 3D printing.

[0006] This application provides a sealing structure for spiral conveying of micro powder in 3D printing, including a housing and a conveying shaft. One end of the conveying shaft is inserted into the housing and connected to the spiral blades. The other end of the conveying shaft is connected to a drive motor. The housing and the conveying shaft are sealed by an annular sealing flange. The sealing flange is fixedly connected to the housing and rotatably connected to the conveying shaft through a bearing.

[0007] The sealing flange has a sealing chamber inside, and a plurality of first sealing rings and second sealing rings are provided in the sealing chamber at axial intervals. The outer walls of the first sealing rings and second sealing rings are in contact with the inner wall of the sealing chamber, and the inner walls of the first sealing rings and second sealing rings are in contact with the outer wall of the conveying shaft, so that the first sealing rings and second sealing rings are radially squeezed between the sealing flange and the conveying shaft.

[0008] A pressure cap is coaxially fixedly connected to the conveying shaft. The pressure cap is located inside the housing and faces the sealing flange. The pressure cap and the sealing flange are spaced apart to form a tortuous labyrinth channel. The inlet of the labyrinth channel leads to the inside of the housing, and the outlet of the labyrinth channel extends to the sealing chamber.

[0009] A dustproof ring is provided at the entrance of the maze passage, and the dustproof ring is axially pressed between the gland and the sealing flange;

[0010] The bearing is located on the side of the sealed chamber away from the housing.

[0011] Compared with existing technologies, the sealing structure for the spiral conveying of micro powder in this application has the following advantages: the labyrinth channel increases the resistance to powder penetration through its tortuous path, initially blocking the powder; the dustproof ring further intercepts the powder at the inlet, reducing the amount of powder entering the labyrinth channel; multiple axially spaced sealing rings form a multi-layer seal, providing multiple barriers to the small amount of powder penetrating the labyrinth channel; the bearing is located on the side of the sealing chamber away from the shell and is protected by the multi-layer sealing structure (dustproof ring, labyrinth, multiple sealing rings), effectively preventing powder from intruding into the bearing, solving the problem of bearing failure due to powder wear in existing technologies, and improving equipment stability and service life.

[0012] In one possible implementation, the first sealing ring is a felt seal, and the second sealing ring is an oil seal, with the felt seal and oil seal alternating along the axial direction. Compared with the prior art, the felt seal is good at adsorbing fine dust, and the oil seal enhances the sealing performance through the grease layer. The alternating combination of the two can exert a synergistic effect, making up for the shortcomings of a single sealing method, significantly improving the sealing effect, and more effectively preventing powder penetration.

[0013] In one possible implementation, the felt seal and the oil seal are axially spaced apart by a retaining spring, which is fixedly engaged with the inner wall of the sealing chamber. Compared with the prior art, the retaining spring can precisely fix the axial relative position of the felt and the oil seal, preventing displacement due to vibration or friction when the conveyor shaft rotates, ensuring the stability of the sealing structure and maintaining a long-term sealing effect.

[0014] In one possible implementation, the sidewall of the sealing flange is provided with multiple radially penetrating discharge holes. One end of each discharge hole opens into the sealing chamber and is located between the first and second sealing rings, while the other end communicates with the outside. Compared with the prior art, a small amount of powder penetrating the front seal can be discharged promptly through the discharge holes, preventing powder accumulation in the sealing chamber; preventing accumulated powder from further penetrating towards the bearing, reducing erosion of the sealing rings and bearings, and extending the service life of the sealing components and bearings.

[0015] In one possible implementation, the plurality of discharge holes are evenly spaced around the circumference. Compared with the prior art, the even circumferential distribution can cover different circumferential positions of the sealed chamber, ensuring that the powder that has permeated into each area can be effectively discharged, avoiding local powder accumulation and improving discharge efficiency.

[0016] In one possible implementation, the dustproof ring is made of felt. Compared to existing technologies, felt has excellent adsorption properties and a dense structure, which can efficiently intercept fine powder at the entrance of the maze passage, strengthen the initial sealing process, and reduce the amount of powder entering the subsequent sealing structure.

[0017] In one possible implementation, the sealing flange is detachably connected to the housing by bolts. Compared with the prior art, the detachable structure facilitates the periodic disassembly of the sealing flange for inspection, maintenance, or replacement of vulnerable components such as sealing rings and dust rings, reducing equipment maintenance difficulty and cost.

[0018] In one possible implementation, the gland is welded to the conveyor shaft. Compared to existing technologies, welding ensures the coaxiality and connection strength between the gland and the conveyor shaft, preventing relative loosening or eccentricity; it also guarantees the structural stability of the labyrinth channel and maintains its long-term sealing effect.

[0019] In one possible implementation, the spacing between the labyrinth channels is no greater than 1 mm. Compared with the prior art, the narrow spacing significantly increases the path resistance for powder penetration, making it difficult for fine-particle-size powder to enter the sealing chamber through the labyrinth channels, thus strengthening the physical barrier effect of the labyrinth structure and improving the overall sealing performance. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this application;

[0021] Figure 2 This is a cross-sectional view of this application;

[0022] Figure 3 for Figure 2 Enlarged view of part of the image;

[0023] Figure 4 This is a half-sectional view of the sealing flange;

[0024] Figure 5 This is a schematic diagram of the conveyor shaft and the pressure cap.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Housing; 2. Conveying shaft; 3. Spiral blade; 4. Drive motor; 5. Sealing flange; 51. Sealing chamber; 52. Discharge hole; 6. Bearing; 71. First sealing ring; 72. Second sealing ring; 8. Pressure cap; 9. Labyrinth channel; 91. First radial channel; 92. Axial channel; 93. Second radial channel; 10. Dustproof ring; 20. Snap ring. Detailed Implementation

[0027] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0028] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0029] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0030] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0031] See Figures 1 to 5 This application discloses a sealed structure for spiral conveying of 3D printing powder, including a housing 1 and a conveying shaft 2. One end of the conveying shaft 2 is inserted into the housing 1 and connected to a spiral blade 3, thereby conveying the 3D printing powder through the rotation of the spiral blade 3; the other end of the conveying shaft 2 is connected to a drive motor 4, which provides power for the rotation of the conveying shaft 2.

[0032] To achieve a seal between the housing 1 and the conveying shaft 2, an annular sealing flange 5 is provided. The sealing flange 5 is fixedly connected to the housing 1 and rotates with the conveying shaft 2 through the bearing 6, ensuring that the conveying shaft 2 can rotate flexibly while also providing it with stable support.

[0033] Specifically, a sealing chamber 51 is provided inside the sealing flange 5, and multiple first sealing rings 71 and second sealing rings 72 are arranged axially within the sealing chamber 51. The outer walls of these sealing rings are tightly fitted with the inner wall of the sealing chamber 51, and the inner walls are tightly fitted with the outer wall of the conveying shaft 2, so that the first sealing rings 71 and the second sealing rings 72 are radially pressed between the sealing flange 5 and the conveying shaft 2. That is, the setting of multiple sealing rings can effectively prevent the penetration of micro powder.

[0034] A pressure cap 8 is coaxially fixedly connected to the conveying shaft 2. The pressure cap 8 is located inside the housing 1 and faces the sealing flange 5. A tortuous labyrinth channel 9 is formed between the pressure cap 8 and the sealing flange 5. The inlet of the labyrinth channel 9 leads to the interior of the housing 1, and the outlet extends to the sealing chamber 51. When the micro powder attempts to leak from the interior of the housing 1 towards the bearing 6, the labyrinth channel 9 provides multiple obstacles, greatly reducing the possibility of micro powder leakage. Specifically, the labyrinth channel 9 includes a first radial channel 91, an axial channel 92, and a second radial channel 93 connected in sequence. The first radial channel 91 faces the interior of the housing 1, and the second radial channel 93 extends to the sealing chamber 51. The first radial channel 91 and the second radial channel 93 are axially spaced apart.

[0035] A dustproof ring 10 is provided in the first radial channel 91 of the maze channel 9. The dustproof ring 10 is axially pressed between the pressure cover 8 and the sealing flange 5, which further enhances the blocking effect on micro powder and reduces the amount of micro powder entering the maze channel 9.

[0036] In addition, the bearing 6 is located on the side of the sealing chamber 51 away from the housing, that is, on the rear side of the sealing chamber 51. This arrangement can prevent the micro powder from directly contacting the bearing 6, effectively protect the bearing 6, prevent bearing 6 failure caused by micro powder intrusion, and improve the stability and service life of the equipment.

[0037] In this embodiment, the first sealing ring 71 is a felt seal, and the second sealing ring 72 is an oil seal. The felt seal and the oil seal are alternately distributed along the axial direction.

[0038] Specifically, the felt seal has good particle adsorption and elasticity, which can effectively block the micro powder; the oil seal has excellent sealing performance, which can further prevent the leakage of micro powder. In addition, the felt seal and the oil seal are alternately distributed along the axial direction. This alternating arrangement can give full play to the advantages of the two sealing methods, form a complement, greatly improve the overall sealing performance of the sealing chamber 51, and more effectively prevent the penetration of 3D printing micro powder.

[0039] In this embodiment, the felt seal and the oil seal are axially spaced apart by a retaining spring 20, which is fixedly engaged with the inner wall of the sealing chamber 51.

[0040] Specifically, the retaining ring 20 is fixedly mounted on the inner wall of the sealing chamber 51. Its main function is to axially position and separate the felt seal and the oil seal, ensuring that the felt seal and the oil seal maintain a stable interval. This prevents them from squeezing or shifting against each other due to vibration or other reasons during equipment operation, thus ensuring that each sealing method can fully exert its sealing effect and maintain the stability and reliability of the sealing structure. Specifically, multiple axially spaced annular grooves are provided on the inner wall of the sealing chamber 51, and the retaining ring 20 is mounted in the annular grooves.

[0041] In this embodiment, the side wall of the sealing flange 5 is provided with a plurality of radially penetrating discharge holes 52. One end of the discharge hole 52 is connected to the sealing chamber 51 and located between the first sealing ring 71 and the second sealing ring 72, and the other end of the discharge hole 52 is connected to the outside.

[0042] Specifically, when a small amount of micro powder breaks through the labyrinth channel 9 and enters the sealing chamber 51, it will accumulate between the sealing rings. At this time, the discharge hole 52 can discharge the accumulated micro powder from the sealing chamber 51 in time, preventing the micro powder from spreading further in the sealing chamber 51, avoiding adverse effects on the subsequent sealing rings and bearings 6, and ensuring the long-term effective operation of the sealing structure.

[0043] In this embodiment, multiple discharge holes 52 are evenly spaced around the circumference.

[0044] Specifically, this distribution method enables the micro powder accumulated in all circumferential directions inside the sealing chamber 51 to be discharged evenly and in a timely manner, avoiding the inability of micro powder in certain areas to be discharged smoothly due to uneven distribution of the discharge holes 52, thereby further improving the discharge effect, ensuring the cleanliness inside the sealing chamber 51, and maintaining the stability of the sealing performance.

[0045] In this embodiment, the dustproof ring 10 is made of felt.

[0046] Specifically, the felt has a dense fibrous structure, which can effectively prevent micro-powder from entering the labyrinth channel 9 through the inlet. At the same time, the felt has a certain degree of elasticity and wear resistance. When squeezed between the gland 8 and the sealing flange 5, it can fit tightly between the two, ensuring a good sealing effect. Moreover, it is not easily damaged during long-term use and has a long service life.

[0047] In this embodiment, the sealing flange 5 is detachably connected to the housing 1 by bolts.

[0048] Specifically, this connection method facilitates the installation and removal of the sealing flange 5. When components such as the sealing ring and dust ring 10 are worn and need to be replaced, or when the inside of the sealing structure needs to be inspected and cleaned, the sealing flange 5 can be removed from the housing 1 simply by unscrewing the bolts. The operation is simple and quick, reducing maintenance costs and difficulties.

[0049] In this embodiment, the pressure cap 8 is welded to the conveying shaft 2.

[0050] Specifically, welding ensures the firmness and sealing of the connection between the pressure cap 8 and the conveying shaft 2, preventing loosening and gaps during high-speed operation of the equipment due to insufficient connection, and preventing leakage of micro powder from the connection point. At the same time, this connection method also ensures the coaxiality of the pressure cap 8 and the conveying shaft 2, ensuring the dimensional accuracy of the labyrinth channel 9 and maintaining its sealing effect.

[0051] In this embodiment, the spacing between the maze passages 9 is no greater than 1 mm.

[0052] Specifically, such a small gap can greatly increase the difficulty for micro powder to pass through the maze channel 9. When the micro powder tries to pass through the maze channel 9, it will continuously collide and rub against the channel wall, and its kinetic energy will gradually decrease, making it difficult to continue moving forward. This effectively blocks the penetration of micro powder, enhances the sealing effect of the maze channel 9, and further improves the sealing performance of the entire sealing structure.

[0053] The beneficial effects of this application include:

[0054] I. Multiple sealing protection effectively blocks micro powder penetration: A stepped seal is formed by the combination design of dustproof ring 10, labyrinth channel 9, and multi-layer sealing rings. Felt dustproof ring 10 intercepts most of the powder at the inlet; labyrinth channel 9 increases the resistance of powder penetration path; and the axially spaced multi-layer sealing rings provide multiple barriers to residual powder, significantly reducing the risk of powder intrusion.

[0055] II. Synergistic Sealing Enhances Efficiency: Felt seals excel at adsorbing fine dust, while oil seals utilize grease to enhance sealing. The two are axially alternating and fixed at a fixed distance by a snap ring 20, playing a synergistic and complementary role, overcoming the limitations of single seals, and significantly improving sealing reliability.

[0056] 3. Material Discharge and Anti-Accumulation: The side wall of the sealing flange 5 is provided with circumferentially evenly distributed discharge holes 52, with the openings located between adjacent sealing rings. This allows for the timely discharge of trace amounts of powder that have penetrated the preceding seal, preventing them from accumulating in the sealing chamber 51, corroding the sealing rings, or further penetrating into the bearing 6, thus ensuring a long-lasting and effective seal.

[0057] IV. Long-term protection of core bearing 6: Bearing 6 is located at the end of the sealed chamber 51 and is strictly protected by the aforementioned multiple sealing structures, effectively isolating it from contact with powder, fundamentally solving the problem of bearing 6 wear failure caused by powder intrusion, extending equipment life and improving operational stability.

[0058] V. Reliable Structure and Easy Maintenance: The welded connection between the gland 8 and the rotating shaft ensures the precision of the labyrinth channel 9; the detachable connection of the sealing flange 5 facilitates the replacement of seals; the narrow spacing of the labyrinth channels 9, with a gap of no more than 1mm, enhances physical barrier. The overall structure balances sealing strength and ease of maintenance.

[0059] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0060] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A sealing structure for spiral conveying of 3D printing powder, comprising a housing and a conveying shaft, one end of the conveying shaft being inserted into the housing and connected to spiral blades, the other end of the conveying shaft being connected to a drive motor, the housing and the conveying shaft being sealed by an annular sealing flange, the sealing flange being fixedly connected to the housing, and the sealing flange being rotatably connected to the conveying shaft via a bearing, characterized in that: The sealing flange has a sealing chamber inside, and a plurality of first sealing rings and second sealing rings are provided in the sealing chamber at axial intervals. The outer walls of the first sealing rings and second sealing rings are in contact with the inner wall of the sealing chamber, and the inner walls of the first sealing rings and second sealing rings are in contact with the outer wall of the conveying shaft, so that the first sealing rings and second sealing rings are radially squeezed between the sealing flange and the conveying shaft. A pressure cap is coaxially fixedly connected to the conveying shaft. The pressure cap is located inside the housing and faces the sealing flange. The pressure cap and the sealing flange are spaced apart to form a tortuous labyrinth channel. The inlet of the labyrinth channel leads to the inside of the housing, and the outlet of the labyrinth channel extends to the sealing chamber. A dustproof ring is provided at the entrance of the maze passage, and the dustproof ring is axially pressed between the gland and the sealing flange; The bearing is located on the side of the sealed chamber away from the housing.

2. The sealing structure for spiral conveying of 3D printing powder according to claim 1, characterized in that, The first sealing ring is a felt seal, and the second sealing ring is an oil seal. The felt seal and the oil seal are alternately distributed along the axial direction.

3. The sealing structure for spiral conveying of 3D printing powder according to claim 2, characterized in that, The felt seal and the oil seal are axially spaced apart by a retaining spring, which is fixedly engaged with the inner wall of the sealing chamber.

4. The sealing structure for spiral conveying of 3D printing powder according to claim 1, characterized in that, The labyrinth passage includes a first radial passage, an axial passage, and a second radial passage connected in sequence. The first radial passage faces the interior of the housing, the dustproof ring is located inside the first radial passage, and the second radial passage extends to the sealing chamber. The first radial passage and the second radial passage are axially spaced apart.

5. The sealing structure for spiral conveying of 3D printing powder according to claim 1, characterized in that, The side wall of the sealing flange is provided with multiple radially penetrating discharge holes. One end of the discharge hole leads into the sealing chamber and is located between the first sealing ring and the second sealing ring. The other end of the discharge hole is connected to the outside.

6. The sealing structure for spiral conveying of 3D printing powder according to claim 5, characterized in that, The multiple discharge holes are evenly spaced around the circumference.

7. The sealing structure for spiral conveying of 3D printing powder according to claim 1, characterized in that, The dustproof ring is made of felt.

8. The sealing structure for spiral conveying of 3D printing powder according to claim 1, characterized in that, The sealing flange is detachably connected to the housing by bolts.

9. The sealing structure for spiral conveying of 3D printing powder according to claim 1, characterized in that, The pressure cap is welded to the conveyor shaft.

10. The sealing structure for spiral conveying of 3D printing powder according to claim 1, characterized in that, The spacing between the maze passages is no greater than 1 mm.

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