Dynamic sealing structure used in high vacuum environment

Abstract

The invention discloses a dynamic sealing structure used in a high vacuum environment, and relates to the field of dynamic sealing, the dynamic sealing structure comprises a vacuum wall located between an atmosphere side and a vacuum side, and the dynamic sealing structure comprises a power assembly, an execution assembly, a rotating shaft, a vacuum pipe and a sealing assembly; the power assembly is located on the atmosphere side, the execution assembly is located on the vacuum side, the movable end of the power assembly is connected with the rotating shaft, the rotating shaft penetrates through the vacuum wall to be connected with the execution assembly, a vacuum pipe is tightly nested in the vacuum wall and penetrates through the rotating shaft, and the two ends of the vacuum pipe are located on the atmosphere side and the vacuum side respectively. The vacuum pipe provides a vacuum environment as a partition cavity, the sealing assemblies are arranged at the two ends, namely the atmosphere side and the vacuum side, of the vacuum pipe correspondingly to form two relatively independent sealing intervals, two radial dynamic seals are formed for the rotating shaft, and even if the sealing assembly on one side leaks slightly, the sealing assembly on the other side can still keep the sealing performance; and the reliability of the sealing structure is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of dynamic sealing technology, and more specifically to a dynamic sealing structure for use in high vacuum environments. Background Technology

[0002] In high-vacuum systems such as particle accelerators and space environment simulations, the internal high temperatures and radiation often necessitate placing motors and transmission mechanisms on the atmospheric side, driving the actuators within the vacuum chamber via rotating shafts or push rods. These operating conditions place stringent requirements on the transmission seals that connect the atmospheric and vacuum sides: ensuring continuous and reliable transmission of rotational motion to meet the demands of unrestricted 360° rotation or high-speed operation, while simultaneously achieving effective isolation between the atmospheric and vacuum sides to prevent the intrusion of gases and particulate matter into the vacuum chamber.

[0003] However, existing technologies face structural contradictions in achieving these requirements. On the one hand, while some sealing methods can satisfy rotational functions, they often rely on complex auxiliary control systems or precision fluid circuits, resulting in a complex overall equipment structure and difficult maintenance. On the other hand, relatively simple sealing methods are usually only suitable for reciprocating motion or small-angle oscillation, and cannot meet the requirements of continuous rotation. In addition, a single sealing interface directly bears the full pressure difference from the atmospheric side to the vacuum side, which is prone to wear and leakage under long-term operation, thus limiting reliability. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a dynamic sealing structure for use in high vacuum environments.

[0005] The objective of this invention can be achieved through the following technical solutions: A dynamic sealing structure for use in high vacuum environments includes a vacuum wall located between the atmospheric side and the vacuum side, comprising: Power components, actuators, rotating shafts, vacuum tubes, and sealing components; The power component is located on the atmospheric side, the actuation component is located on the vacuum side, the movable end of the power component is connected to the rotating shaft, the rotating shaft passes through the vacuum wall and is connected to the actuation component, a vacuum tube is tightly nested inside the vacuum wall, the rotating shaft passes through the vacuum tube, and the two ends of the vacuum tube are located on the atmospheric side and the vacuum side, respectively. The sealing assembly is provided in two sets, which are located at both ends of the vacuum tube and are in close contact with the outer ring of the rotating shaft. The sealing assembly is used to radially seal the rotating shaft.

[0006] As a further aspect of the present invention: the sealing assembly includes a connecting flange fixedly connected to the end face of the vacuum tube, a sealing flange fixedly installed on the side of the connecting flange away from the vacuum tube, and a sealing element disposed between the connecting flange and the sealing flange, wherein the inner ring of the sealing element is in contact with the rotating shaft, and the rotating shaft passes through the sealing flange and the connecting flange.

[0007] As a further aspect of the present invention: a first groove is provided on the side of the connecting flange facing the sealing flange, the sealing element is nested in the first groove, a second groove is provided on the side of the sealing flange facing the connecting flange, and a pressure cap is fitted inside the second groove, the pressure cap being used to axially limit the sealing element.

[0008] As a further aspect of the present invention: the sealing element includes a sealing ring fitted in the first groove and an annular metal skeleton fitted in the sealing ring. The cross-sections of the annular metal skeleton and the sealing ring are both U-shaped and the openings face the cover plate. The annular metal skeleton is elastic.

[0009] As a further aspect of the present invention: the sealing ring has a middle section and two expansion sections adjacent to the middle section respectively, the annular metal skeleton is configured to act on the two expansion sections through its elastic restoring force to make them open outward, and the opposite surfaces of the two expansion sections respectively abut against the inner wall of the groove and the circumferential surface of the rotating shaft.

[0010] As a further aspect of the present invention: the two spreading sections extend opposite each other at their ends away from the middle section, and the open end face of the annular metal skeleton abuts against the blocking edge.

[0011] As a further aspect of the present invention: a third groove is provided inside the sealing flange, and a bearing is provided inside the third groove, wherein the inner ring of the bearing is in contact with the surface of the rotating shaft.

[0012] As a further embodiment of the present invention: a limiting plate is provided inside the sealing flange, the limiting plate is located on the side of the bearing away from the vacuum tube, and the limiting plate is in close contact with the side of the bearing to axially limit the bearing within the third groove.

[0013] As a further aspect of the present invention: the sealing ring is made of high-performance polymer material, and the annular metal skeleton is made of corrosion-resistant metal.

[0014] As a further aspect of the present invention: the side of the vacuum tube is provided with a vacuum port for connecting to an external vacuum pumping device.

[0015] The beneficial effects of this invention include, but are not limited to: the vacuum tube of this invention provides a vacuum environment as an isolation cavity, and sealing components are respectively set at both ends of the vacuum tube, namely the atmospheric side and the vacuum side, to form two relatively independent sealing zones, forming two radial dynamic seals for the rotating shaft. Even if a small amount of leakage occurs in the sealing component on one side, the sealing component on the other side can still maintain its sealing performance, which significantly improves the reliability of this sealing structure. At the same time, the separate arrangement of the power component and the actuator on the atmospheric side and the vacuum side realizes the physical isolation between the power source and the vacuum working area, avoiding the contamination of the vacuum environment by atmospheric side equipment such as motors, and realizing the effective transmission of atmospheric side power to vacuum side actuator. In addition, this structure adopts a purely mechanical double-end sealing layout, and the rotating shaft passes through the vacuum tube to form a rotation transmission channel. It can realize the unobstructed transmission of atmospheric side power to vacuum side without relying on complex magnetic field generating devices or fluid control systems. Moreover, the 360-degree rotation of the rotating shaft is unrestricted, meeting the requirements of high vacuum equipment for continuous rotation. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a cross-sectional view of the overall structure of an embodiment of the present invention; Figure 3 This is the present invention. Figure 3 Enlarged view of point A in the image; Figure 4 This is a partial structural schematic diagram of a cross-sectional view of a sealing assembly according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached drawings: 1. Vacuum wall; 2. Power assembly; 3. Actuation assembly; 4. Rotating shaft; 5. Vacuum tube; 6. Sealing assembly; 61. Connecting flange; 62. Sealing flange; 63. Seal; 611. First groove; 621. Second groove; 64. Gland; 631. Sealing ring; 632. Annular metal frame; 631a. Intermediate section; 631b. Spreading section; 631c. Side flange; 622. Third groove; 65. Bearing; 66. Limiting plate; 51. Vacuum extraction port. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] See Figures 1-2 An embodiment of the present invention provides a dynamic sealing structure for use in a high vacuum environment, comprising a vacuum wall 1 located between the atmospheric side and the vacuum side, including: a power component 2, an actuation component 3, a rotating shaft 4, a vacuum tube 5, and a sealing component 6; the power component 2 is located on the atmospheric side, the actuation component 3 is located on the vacuum side, and the movable end of the power component 2 is connected to the rotating shaft 4. In use, starting the power component 2 will drive the rotating shaft 4 to rotate. The rotating shaft 4 passes through the vacuum wall 1 and is connected to the actuation component 3. The vacuum tube 5 is tightly nested inside the vacuum wall 1, and the rotating shaft 4 passes through the vacuum tube 5. The two ends of the vacuum tube 5 are located on the atmospheric side and the vacuum side, respectively, and the vacuum tube 5 is evacuated; wherein, two sets of sealing components 6 are provided, the two sets of sealing components 6 are located at the two ends of the vacuum tube 5 and are tightly attached to the outer ring of the rotating shaft 4, and the sealing components 6 are used to radially seal the rotating shaft 4.

[0021] Specifically, the vacuum tube 5 provides a vacuum environment as an isolation chamber. Sealing components 6 are set at both ends of the vacuum tube 5, namely the atmospheric side and the vacuum side, to form two relatively independent sealing zones, creating two radial dynamic seals for the rotating shaft 4. Even if a small amount of leakage occurs in one sealing component 6, the sealing component 6 on the other side can still maintain its sealing performance, significantly improving the reliability of this sealing structure. At the same time, the separate arrangement of the power component 2 and the actuator 3 on the atmospheric side and the vacuum side achieves physical isolation between the power source and the vacuum working area, avoiding contamination of the vacuum environment by atmospheric side equipment such as motors, and realizing the effective transmission of atmospheric side power to the vacuum side actuator. In addition, this structure adopts a purely mechanical double-end sealing layout. The rotating shaft 4 passes through the vacuum tube 5 to form a rotation transmission channel. It can realize the unobstructed transmission of atmospheric side power to the vacuum side without relying on a complex magnetic field generating device or fluid control system. Furthermore, the 360-degree rotation of the rotating shaft 4 is unrestricted, meeting the requirements of high vacuum equipment for continuous rotation.

[0022] See Figures 2-3 Optionally, the sealing assembly 6 includes a connecting flange 61 fixedly connected to the end face of the vacuum tube 5, a sealing flange 62 fixedly installed on the side of the connecting flange 61 away from the vacuum tube 5, and a sealing element 63 disposed between the connecting flange 61 and the sealing flange 62. The inner ring of the sealing element 63 fits against the rotating shaft 4, the rotating shaft 4 passes through the sealing flange 62 and the connecting flange 61, and the sealing flange 62 and the connecting flange 61 are detachably installed together by bolts evenly distributed around the circumference of the two flanges, which facilitates the replacement and maintenance of the sealing element 63.

[0023] See Figures 2-3Optionally, the connecting flange 61 has a first groove 611 on the side facing the sealing flange 62, and the sealing element 63 is nested in the first groove 611. The sealing flange 62 has a second groove 621 on the side facing the connecting flange 61, and a pressure cap 64 is fitted inside the second groove 621. The pressure cap 64 is used to axially limit the sealing element 63.

[0024] In this embodiment, the seal 63 is used to radially seal the rotating shaft 4, and the cover 64 is used to axially limit the seal 63 in the first groove 611. The coordinated cooperation of the first groove 611 and the cover plate achieves both radial and axial limiting of the seal 63, preventing the rotating shaft 4 from radially twisting when rotating at high speed.

[0025] See Figures 2-4 Optionally, the sealing element 63 includes a sealing ring 631 fitted in the first groove 611 and an annular metal skeleton 632 fitted in the sealing ring 631. The cross-sections of the annular metal skeleton 632 and the sealing ring 631 are both U-shaped and the openings face the cover plate. The annular metal skeleton 632 is elastic.

[0026] In this embodiment, the annular metal skeleton 632 can provide continuous radial elastic force to the sealing ring 631 to compensate for the material creep and wear of the sealing ring 631 during long-term use, so that the lip of the sealing ring 631 can always maintain an appropriate clamping force on the surface of the rotating shaft 4. At the same time, the rigid support of the annular metal skeleton 632 can prevent the sealing ring 631 from being excessively deformed or sucked in under the action of vacuum pressure difference, ensuring that the sealing element 63 has long-term stable sealing performance.

[0027] See Figures 2-4 Optionally, the sealing ring 631 has a middle section 631a and two expansion sections 631b adjacent to the middle section 631a respectively. The annular metal skeleton 632 is configured to open outward by acting on the two expansion sections 631b through its elastic restoring force. The opposite sides of the two expansion sections 631b abut against the inner wall of the groove and the circumferential surface of the rotating shaft 4 respectively. A sealing side is formed between the opposite sides of the two expansion sections 631b and the groove, the abutment with the rotating shaft 4, and the inner wall of the groove.

[0028] In this embodiment, because the annular metal frame 632 provides a continuous elastic clamping force to the two expanding sections 631b of the sealing ring 631, pressing the two expanding sections 631b against the inner wall of the first groove 611, and because the cross-sections of both the annular metal frame 632 and the sealing ring 631 are U-shaped with their openings facing the cover plate, a sealing side is formed between the contact points of the opposite sides of the two expanding sections 631b with the groove, the contact points with the rotating shaft 4, and the inner wall of the groove. A pressure difference is formed between the opening side and the sealing side of the sealing ring 631, especially when it is set in the atmosphere. The sealing assembly 6 on the side has a seal 63 located inside the connecting flange 61 connected to the vacuum tube 5, and a cover plate located inside the sealing flange 62. The cover plate is located on the side of the seal 63 away from the vacuum tube 5. Some gas may leak from between the cover plate and the rotating shaft 4 into the first groove 611. The opening side of the sealing ring 631 faces the cover plate. The pressure difference between the atmospheric side and the sealing side acts on the sealing ring 631, which, combined with the elasticity of the annular metal skeleton 632, forms a self-tightening sealing effect. The higher the vacuum level on the sealing side, the stronger the adhesion of the lip of the sealing ring 631 to the rotating shaft 4.

[0029] See Figures 2-4 Optionally, the two spanning sections 631b have a retaining edge 631c extending from one end away from the middle section 631a, and the open end face of the annular metal frame 632 abuts against the retaining edge 631c.

[0030] In this embodiment, the retaining edge 631c provides a reliable axial limit for the annular metal skeleton 632, preventing the annular metal skeleton 632 from coming out of the sealing ring 631 under high-speed rotation or vibration conditions. In addition, the contact fit between the retaining edge 631c and the end face of the annular metal skeleton 632 forms an effective force transmission path, so that the elastic restoring force of the skeleton can be fully applied to the spreading section 631b.

[0031] See Figures 2-3 Optionally, a third groove 622 is provided in the sealing flange 62, and a bearing 65 is provided in the third groove 622. The inner ring of the bearing 65 is in contact with the surface of the rotating shaft 4.

[0032] In this embodiment, two bearings 65 are provided. The bearings 65 provide precise radial support for the rotating shaft 4, effectively reducing the radial runout and sway of the rotating shaft 4 when it is running at high speed, thereby alleviating the uneven wear of the lip of the seal 63.

[0033] See Figures 2-3 Optionally, a limiting plate 66 is provided inside the sealing flange 62. The limiting plate 66 is located on the side of the bearing 65 away from the vacuum tube 5. The limiting plate 66 is in close contact with the side of the bearing 65 to axially limit the bearing 65 within the third groove 622. The limiting plate 66 can also be used as a dust cover to prevent particles from the atmospheric side or the vacuum side from entering the bearing 65.

[0034] Optionally, the sealing ring 631 is made of high-performance polymer material, and the annular metal skeleton 632 is made of corrosion-resistant metal.

[0035] In this embodiment, high-performance polymeric materials (such as perfluoroether rubber, polyimide, etc.) with low outgassing rate, high and low temperature resistance, and radiation resistance are selected according to the specific working conditions of the high vacuum environment. See Figures 1-2 Optionally, the side of the vacuum tube 5 is provided with a vacuum port 51 for connecting to an external vacuum pumping device.

[0036] In this embodiment, an external vacuum pumping device is connected to the vacuum port 51 to evacuate the vacuum tube 5, so that the vacuum tube 5 forms a buffer cavity between the two sealing components 6. A gas detection device can be installed in the vacuum tube 5. Even if a small amount of leakage occurs in the atmospheric side sealing component 6, the leaked gas will be promptly drawn away from the vacuum port 51 and cannot directly enter the vacuum side, thereby effectively reducing the leakage rate of the system.

[0037] Furthermore, common solutions in existing technologies include: mechanical seals: relying on end-face contact, but lubrication is difficult under high vacuum, they are prone to wear and particle generation, and have a short lifespan; lip seal rubber rings (such as fluororubber): although low in cost, they have serious outgassing, limited temperature resistance, and short lifespan, and cannot meet the requirements of ultra-high vacuum; pure magnetohydrodynamic seals: although they can achieve contactless sealing, they are sensitive to shaft runout, strong vibration and thermal deformation, and are prone to failure under long stroke or large temperature difference conditions, and are also costly; metal bellows seals: suitable for reciprocating, oscillating or small-angle rotation, but the stroke / angle is limited, making it difficult to use in high-speed rotation applications, and high-frequency motion is prone to fatigue failure.

[0038] This invention uses a U-shaped sealing ring 631 made of high-performance polymer material to replace the traditional metal end face or rubber lip. It reduces the coefficient of friction by utilizing the solid lubrication properties of the material itself, eliminating the need for lubricating oil and metal shavings contamination. Furthermore, an elastic annular metal skeleton 632 is set in the U-shaped cavity of the sealing ring 631 to form a spring energy storage structure. The elastic restoring force of the annular metal skeleton 632 can continuously compensate for radial displacement fluctuations caused by shaft eccentricity, vibration and thermal deformation, and maintain the stability of the lip sealing pressure. This overcomes the problems of sensitive gaps in magnetohydrodynamic seals and bellows fatigue failure.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., 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; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A dynamic sealing structure for use in a high vacuum environment, comprising a vacuum wall (1) between an atmospheric side and a vacuum side, characterized in that, The utility model relates to a rotary shaft sealing assembly of vacuum valve, including: Power assembly (2), execution assembly (3), rotating shaft (4), vacuum pipe (5) and sealing assembly (6); The power assembly (2) is located in the atmosphere side, the execution assembly (3) is located in the vacuum side, the movable end of power assembly (2) is connected with rotating shaft (4), rotating shaft (4) passes through vacuum wall (1) and is connected with execution assembly (3), vacuum pipe (5) is closely nested in vacuum wall (1), rotating shaft (4) penetrates vacuum pipe (5), and both ends of vacuum pipe (5) are located in the atmosphere side and the vacuum side respectively; Wherein, the sealing assembly (6) is provided with two groups, and the sealing assembly (6) is located in the two ends of vacuum pipe (5) and tightly adheres to the outer ring of rotating shaft (4) respectively, and the sealing assembly (6) is used for the radial sealing of rotating shaft (4).

2. The dynamic sealing structure for use in a high vacuum environment according to claim 1, wherein, The sealing assembly (6) includes the connecting flange (61) fixedly connected to the end surface of the vacuum pipe (5), the sealing flange (62) fixedly installed on the side, away from the vacuum pipe (5), of the connecting flange (61) and the sealing element (63) arranged between the connecting flange (61) and the sealing flange (62), the inner ring of the sealing element (63) is attached to the rotating shaft (4), and the rotating shaft (4) penetrates the sealing flange (62) and the connecting flange (61).

3. Dynamic sealing structure for use in a high vacuum environment according to claim 2, characterized in that, The side of the connecting flange (61) towards the sealing flange (62) is provided with a first groove (611), the sealing element (63) is nested in the first groove (611), the side of the sealing flange (62) towards the connecting flange (61) is provided with a second groove (621), the second groove (621) is provided with a gland (64), and the gland (64) is used for axially limiting the sealing element (63).

4. The dynamic sealing structure for use in a high vacuum environment according to claim 3, wherein, The sealing element (63) includes a sealing ring (631) nested in the first groove (611) and an annular metal skeleton (632) nested in the sealing ring (631), the cross sections of the annular metal skeleton (632) and the sealing ring (631) are all U-shaped and open towards the cover plate, and the annular metal skeleton (632) is elastic.

5. The dynamic sealing structure for use in a high vacuum environment according to claim 4, wherein, The sealing ring (631) has a middle section (631a) and two open sections (631b) adjacent to the middle section (631a) respectively, the annular metal skeleton (632) is configured to act on the two open sections (631b) by the elastic restoring force thereof to make the two open sections (631b) open outwards, and the opposite surfaces of the two open sections (631b) respectively abut against the inner wall of the groove and the circumferential surface of the rotating shaft (4).

6. The dynamic sealing structure for use in a high vacuum environment of claim 5, wherein, The opposite ends of the two open sections (631b) away from the middle section (631a) extend oppositely with a stop edge (631c), and the opening end surface of the annular metal skeleton (632) abuts against the stop edge (631c).

7. The dynamic sealing structure for use in a high vacuum environment according to claim 6, characterized in that, The sealing flange (62) is provided with a third groove (622) therein, the third groove (622) is provided with a bearing (65) therein, and the inner ring of the bearing (65) abuts against the surface of the rotating shaft (4).

8. The dynamic sealing structure for use in a high vacuum environment of claim 7, wherein, A limiting plate (66) is arranged in the sealing flange (62), and the limiting plate (66) is located on the side of the bearing (65) away from the vacuum pipe (5), and the limiting plate (66) is tightly attached to the side of the bearing (65) to axially limit the bearing (65) in the third groove (622).

9. The dynamic sealing structure for use in a high vacuum environment of claim 4, wherein, The sealing ring (631) is made of high-performance polymer material, and the annular metal framework (632) is made of corrosion-resistant metal.

10. The dynamic sealing structure for use in a high vacuum environment of claim 1, wherein, The vacuum pipe (5) is provided with a vacuum suction port (51) on the side for being connected with external vacuumizing equipment.

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