Magnetic fluid bellows combined seal structure

Abstract

The application relates to a magnetic fluid bellows combined sealing structure, and belongs to the technical field of sealing. The magnetic fluid bellows combined sealing structure comprises a bellows sealing piece and a magnetic fluid sealing piece. The bellows sealing piece is provided with a fixed end and a movable end. The fixed end of the bellows sealing piece is used for being connected with a vacuum equipment cavity. One end of the magnetic fluid sealing piece is connected with the movable end of the bellows sealing piece, and the other end is used for being connected with a driving mechanism shell of a long shaft. The magnetic fluid sealing piece and the bellows sealing piece are both sleeved outside the long shaft. The bellows sealing piece comprises a plurality of bellows units which are sequentially connected. A transition ring is arranged between adjacent bellows units. One end of the plurality of bellows units close to the vacuum equipment cavity serves as the fixed end, and the other end far away from the vacuum equipment cavity serves as the movable end. The application has the effect of facilitating sealing between a long shaft which needs to be axially fed and rotated and a device cavity with high vacuum degree.

Description

Technical Field

[0001] This application relates to the field of sealing technology, and in particular to a magnetic fluid bellows combined sealing structure. Background Technology

[0002] Vacuum coating and vacuum heat treatment equipment not only requires a high degree of vacuum but also involves a long shaft for material transfer. This long shaft needs to reciprocate as it extends into or out of the vacuum equipment cavity to feed materials, and it also needs to be driven by a drive mechanism to rotate and adjust the orientation of the workpiece. When the long shaft needs to be fed, a linear module drives the entire drive mechanism and the long shaft to move back and forth as a whole; when the long shaft needs to be rotated, the drive mechanism drives the long shaft to rotate.

[0003] Because the cavity of vacuum equipment needs to maintain a high vacuum level during operation, sealing the cavity between a long shaft that requires both axial feeding and rotation is quite challenging. Utility Model Content

[0004] To facilitate sealing between a long shaft that requires both axial feed and rotation and a device cavity that requires high vacuum, this application provides a magnetohydrodynamic bellows combined sealing structure.

[0005] The magnetic fluid bellows combined sealing structure provided in this application adopts the following technical solution: A magnetohydrodynamic bellows combined sealing structure includes: A bellows seal having a fixed end and a movable end, wherein the fixed end of the bellows seal is used to connect to the cavity of a vacuum device; A magnetic fluid seal, one end of which is connected to the movable end of a bellows seal, and the other end is used to connect to the drive mechanism housing of a long shaft. Both the magnetic fluid seal and the bellows seal are sleeved on the outside of the long shaft. The bellows seal includes multiple bellows units connected in sequence, with a transition ring between adjacent bellows units. The end of each bellows unit closer to the vacuum equipment cavity is a fixed end, and the end farther from the vacuum equipment cavity is a movable end.

[0006] Preferably, each of the bellows units includes a plurality of waveplates welded in sequence, wherein the inner edge of the waveplate is welded to the inner edge of the adjacent waveplate on one side, and the outer edge of the waveplate is welded to the outer edge of the adjacent waveplate on the other side.

[0007] Preferably, the cross-section of the waveplate in the axial direction is a curved waveform.

[0008] Preferably, the waveplate is made of 316 stainless steel.

[0009] Preferably, the bellows unit near one end of the vacuum equipment cavity is connected to a flange, the flange is connected to the vacuum equipment cavity, and a first sealing ring is provided between the flange and the vacuum equipment cavity.

[0010] Preferably, the bellows unit near one end of the magnetic fluid seal is provided with a connector, the connector is connected to the magnetic fluid seal, and a second sealing ring is provided between the connector and the magnetic fluid seal.

[0011] Preferably, the connector and the magnetohydrodynamic seal are connected by bolts, and the connector has a first annular groove for accommodating the bolt head on the connector.

[0012] Preferably, the magnetic fluid seal is connected to the drive mechanism housing by bolts, and a second annular groove is provided on the outer wall of the magnetic fluid seal for accommodating the bolt head on the magnetic fluid seal.

[0013] Preferably, the bottom wall of the second annular groove has an opening that radially penetrates the magnetohydrodynamic seal along its long axis.

[0014] Preferably, the magnetic fluid seal has a clearance fit with a magnetic guide sleeve, which is used to fix it on the long shaft. A third sealing ring is provided between the magnetic guide sleeve and the long shaft, and the second annular groove is located on the side of the magnetic guide sleeve near the drive mechanism.

[0015] In summary, this application includes the following beneficial technical effects: 1. The rotating long shaft is sealed by magnetic fluid between the magnetic fluid seal and the long shaft, while the bellows seal can adapt to the back and forth movement of the long shaft and its drive mechanism, thereby ensuring the high vacuum degree in the vacuum equipment cavity. This achieves the sealing between the long shaft that requires both axial feed and rotation and the equipment cavity that requires high vacuum degree. It can be widely used in similar high vacuum degree requirements and long shaft sealing conditions with axial feed and rotation. 2. Meanwhile, the bellows seal is formed by connecting multiple bellows units with a transition ring, which can not only be used for long shafts with large lengths, but also can be combined into bellows seals of specific lengths as needed. Attached Figure Description

[0016] Figure 1 This is a horizontal schematic diagram of the overall structure of Embodiment 1 of this application.

[0017] Figure 2 This is a partial cross-sectional lateral view of Embodiment 1 of this application.

[0018] Figure 3This is a schematic diagram of the overall structure of the magnetohydrodynamic seal in Embodiment 1 of this application.

[0019] Figure 4 This is a schematic diagram of the waveplate structure in Embodiment 2 of this application.

[0020] Explanation of reference numerals in the attached drawings: 1. Bellows unit; 11. Wave plate; 2. Vacuum equipment cavity; 3. Magnetohydrodynamic seal; 4. Drive mechanism; 5. Transition ring; 6. Flange; 7. First sealing ring; 8. Connector; 9. Second sealing ring; 10. First annular groove; 12. Second annular groove; 13. Opening; 14. Magnetic guide sleeve. Detailed Implementation

[0021] The following combination Figures 1-4 This application will be described in further detail.

[0022] Example 1: This application discloses a magnetohydrodynamic bellows combined sealing structure. (Refer to...) Figure 1 and Figure 2 The magnetic fluid bellows combined sealing structure includes a bellows seal and a magnetic fluid seal 3. The bellows seal has a fixed end and a movable end. The fixed end of the bellows seal is used to connect with the vacuum equipment cavity 2. The vacuum equipment cavity 2 refers to a solid with a vacuum working chamber, not a virtual body. The extension direction of the bellows seal is parallel to the axis of the long axis (not shown in the figure). The length of the long axis is greater than 2m. One end of the magnetic fluid seal 3 is connected to the movable end of the bellows seal, and the other end is used to connect with the housing of the drive mechanism 4 of the long axis. Both the magnetic fluid seal 3 and the bellows seal are sleeved on the outside of the long axis. Specifically, the long axis and the magnetic fluid seal 3 are clearance-fitted, while the long axis moves through the bellows seal, so that the bellows seal does not interfere with the movement and rotation of the long axis.

[0023] Reference Figure 1 and Figure 2 Furthermore, the bellows seal includes multiple bellows units 1 connected in sequence, with a transition ring 5 welded between adjacent bellows units 1. One end of the multiple bellows units 1 that is closer to the vacuum equipment cavity 2 serves as a fixed end and is connected to the vacuum equipment cavity 2; while the other end that is farther away from the vacuum equipment cavity 2 serves as a movable end and is connected to the magnetohydrodynamic seal 3.

[0024] When the long shaft needs to be fed, the entire drive mechanism 4 and the long shaft are driven to move back and forth as a whole by the external linear module. During this process, the bellows seal can adapt to the back and forth movement of the long shaft and its drive mechanism 4. When the long shaft needs to be driven to rotate, the drive mechanism 4 drives the long shaft to rotate and injects magnetic fluid into the magnetic fluid seal 3. Under the action of the magnetic field of the magnetic fluid seal 3, the magnetic fluid between the magnetic fluid seal 3 and the long shaft forms a liquid O-ring to seal the rotating long shaft. Thus, with the cooperation of the bellows seal and the magnetic fluid seal 3, the high vacuum degree in the vacuum equipment cavity 2 is effectively guaranteed. This achieves the sealing between the long shaft that needs both axial feed and rotation and the equipment cavity that requires high vacuum degree. It can be widely used in sealing conditions of long shafts with similar high vacuum degree requirements and axial feed and rotation. At the same time, the bellows seal is composed of multiple bellows units 1 connected to the transition ring 5. It can not only be used for long shafts with large lengths, but can also be combined into bellows seals of specific lengths as needed.

[0025] Reference Figure 1 and Figure 2 To facilitate the connection between the bellows seal and the vacuum equipment cavity 2, a flange 6 is welded and fixed to the end of the bellows unit 1 near the vacuum equipment cavity 2. The flange 6 is fixed to the vacuum equipment cavity 2 by multiple bolts. A first sealing ring 7 is provided between the flange 6 and the vacuum equipment cavity 2. Specifically, a first mounting groove (not shown in the figure) is opened circumferentially on the side of the flange 6 near the vacuum equipment cavity 2. The first sealing ring 7 is embedded in the first mounting groove and abuts tightly against the vacuum equipment cavity 2. The bellows unit 1 and the vacuum equipment cavity 2 are connected by the flange 6 and bolts, which is convenient for disassembly and assembly. The first sealing ring 7 can achieve a static seal between the fixed end of the bellows seal and the vacuum equipment cavity 2, which helps to ensure the vacuum level in the vacuum equipment cavity 2.

[0026] Reference Figure 1 and Figure 2The magnetohydrodynamic (MHD) seal 3 is existing technology, and its specific structure and principle will not be elaborated here. To facilitate the sealing connection between the movable end of the bellows seal and the MHD seal 3, a connector 8 is welded and fixed to the end of the bellows unit 1 near the MHD seal 3. The connector 8 is cylindrical, and the side of the connector 8 away from the bellows unit 1 is fixed to the outer shell of the MHD seal 3 by multiple bolts. A second sealing ring 9 is provided between the connector 8 and the outer shell of the MHD seal 3. Specifically, a second mounting groove (not shown in the figure) is opened circumferentially on the end face of the connector 8 near the MHD seal 3. The second sealing ring 9 is embedded in the second mounting groove and tightly abuts against the outer shell of the MHD seal 3. The second sealing ring 9 achieves a static seal between the movable end of the bellows seal and the outer shell of the MHD seal 3, which helps to ensure the vacuum level in the vacuum equipment cavity 2.

[0027] Reference Figure 1 and Figure 2 To facilitate the arrangement of bolts on the connector 8, a first annular groove 10 is provided on the outer wall of the connector 8 along its circumference. The first annular groove 10 makes the axial section of the connector 8 I-shaped. The axial direction of the bolts on the connector 8 is parallel to the axial direction of the connector 8. The first annular groove 10 is used to accommodate the bolt heads on the connector 8, thereby facilitating the connection between the connector 8 and the magnetic fluid seal 3 and making it convenient for the operator to install and operate.

[0028] Reference Figure 1 and Figure 3 To facilitate the connection between the magnetic fluid seal 3 and the drive mechanism 4, the outer shell of the magnetic fluid seal 3 is fixed to the housing of the drive mechanism 4 by bolts. A second annular groove 12 is provided on the outer wall of the magnetic fluid seal 3 near the drive mechanism 4 along its circumference. The bolt connected to the outer shell of the magnetic fluid seal 3 is axially parallel to the axial direction of the magnetic fluid seal 3. The second annular groove 12 is used to accommodate the bolt head connected to the magnetic fluid seal 3. The setting of the second annular groove 12 facilitates the assembly of the magnetic fluid seal 3 and the housing of the drive mechanism 4.

[0029] Reference Figure 1 and Figure 3 The second annular groove 12 has two openings 13 at opposite positions. The openings 13 penetrate the magnetic fluid seal 3 radially along the long axis. The openings 13 facilitate the detection of the geometric accuracy and alignment of the long axis by the detection equipment mounted on the housing of the drive mechanism 4.

[0030] Reference Figure 1 , Figure 2 and Figure 3A magnetically conductive sleeve 14 is fitted inside the magnetohydrodynamic seal 3 with a clearance fit. The magnetically conductive sleeve 14 is used to fix the long shaft. Specifically, the magnetically conductive sleeve 14 and the long shaft are fixed with an interference fit. At the same time, a third sealing ring (not shown in the figure) is provided between the magnetically conductive sleeve 14 and the long shaft, and the third sealing ring is embedded in the inner side of the magnetically conductive sleeve 14. The second annular groove 12 is located on the side of the magnetically conductive sleeve 14 near the drive mechanism 4. The magnetically conductive sleeve 14 helps to replace the long shaft as part of the magnetic circuit, reduces the requirements for the material of the long shaft, and facilitates processing and maintenance.

[0031] The implementation principle of Embodiment 1 of this application is as follows: When the long shaft needs to be fed, the entire drive mechanism 4 and the long shaft are driven to move back and forth as a whole by the external linear module. During this process, the bellows seal can adapt to the back and forth movement of the long shaft and the drive mechanism 4 and ensure the high vacuum degree in the vacuum equipment cavity 2. When the long shaft needs to be driven to rotate, the drive mechanism 4 drives the long shaft to rotate. By injecting magnetic fluid into the magnetic fluid seal 3, under the action of the magnetic field of the magnetic fluid seal 3, the magnetic fluid between the magnetic fluid seal 3 and the magnetic guide sleeve 14 on the long shaft forms a liquid O-ring seal, thereby achieving a seal without mechanical contact. The magnetic fluid seal can be used in equipment that requires frequent start-stop, long-term static or high-speed rotation, thereby achieving the sealing between the long shaft that requires both axial feed and rotation and the equipment cavity that requires high vacuum degree. It can be widely used in sealing conditions of long shafts with similar high vacuum degree requirements and axial feed and rotation.

[0032] Meanwhile, the bellows seal is formed by connecting multiple bellows units 1 with transition rings 5, which can not only be used for long shaft feeding conditions with large lengths, but also can be combined into bellows seals of specific lengths as needed.

[0033] Example 2: Reference Figure 2 and Figure 4 The difference between this embodiment and Embodiment 1 is that each bellows unit 1 includes multiple corrugated plates 11 welded sequentially. The inner edge of each corrugated plate 11 is welded to the inner edge of the adjacent corrugated plate 11, and the outer edge is welded to the outer edge of the adjacent corrugated plate 11 on the other side. The bellows unit 1 is formed by welding the inner and outer edges of multiple corrugated plates 11 sequentially. Specifically, the corrugated plates 11 are made of 316 stainless steel, which has good wear resistance and helps to extend the service life of the bellows unit 1. Furthermore, the cross-section of the corrugated plate 11 in the axial direction is a curved waveform, that is, after the corrugated plate 11 is cut along a direction parallel to the axis, its end cross-section is a curved waveform.

[0034] The implementation principle of Embodiment 2 of this application is as follows: the bellows unit 1 is formed by welding multiple wave plates 11 in sequence, so that the shape of the wave plate 11 can be customized as needed, and the length can be combined as needed; the wave plate 11 is designed as a curved waveform along the axial direction, which can withstand large compression and expand the compression or stretching range.

[0035] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A magnetic fluid bellows combined sealing structure, characterized in that, include: A bellows seal has a fixed end and a movable end, the fixed end of which is used to connect to the cavity (2) of the vacuum equipment. Magnetic fluid seal (3), one end of which is connected to the movable end of the bellows seal, and the other end is used to connect to the housing of the drive mechanism (4) of the long shaft. Both the magnetic fluid seal (3) and the bellows seal are sleeved on the outside of the long shaft. The bellows seal includes multiple bellows units (1) connected in sequence. A transition ring (5) is provided between adjacent bellows units (1). One end of the multiple bellows units (1) that is closer to the vacuum equipment cavity (2) is a fixed end, and the other end that is farther away from the vacuum equipment cavity (2) is a movable end.

2. The magnetic fluid bellows combined sealing structure according to claim 1, characterized in that: Each of the bellows units (1) includes a plurality of waveplates (11) welded in sequence, the inner edge of the waveplate (11) being welded to the inner edge of the adjacent waveplate (11) on one side, and the outer edge of the waveplate (11) being welded to the outer edge of the adjacent waveplate (11) on the other side.

3. The magnetic fluid bellows combined sealing structure according to claim 2, characterized in that: The cross-section of the waveplate (11) in the axial direction is a curved waveform.

4. The magnetic fluid bellows combined sealing structure according to claim 2, characterized in that: The waveplate (11) is made of 316 stainless steel.

5. The magnetic fluid bellows combined sealing structure according to claim 1, characterized in that: A bellows unit (1) near one end of the vacuum equipment cavity (2) is connected to a flange (6), the flange (6) is connected to the vacuum equipment cavity (2), and a first sealing ring (7) is provided between the flange (6) and the vacuum equipment cavity (2).

6. The magnetic fluid bellows combined sealing structure according to claim 1, characterized in that: A bellows unit (1) near one end of the magnetic fluid seal (3) is provided with a connector (8), which is connected to the magnetic fluid seal (3), and a second sealing ring (9) is provided between the connector (8) and the magnetic fluid seal (3).

7. The magnetic fluid bellows combined sealing structure according to claim 6, characterized in that: The connector (8) is connected to the magnetic fluid seal (3) by bolts. The connector (8) has a first annular groove (10) for accommodating the bolt head on the connector (8).

8. The magnetic fluid bellows combined sealing structure according to claim 1, characterized in that: The magnetic fluid seal (3) is connected to the housing of the drive mechanism (4) by bolts. A second annular groove (12) is provided on the outer wall of the magnetic fluid seal (3). The second annular groove (12) is used to accommodate the bolt head on the magnetic fluid seal (3).

9. The magnetic fluid bellows combined sealing structure according to claim 8, characterized in that: The bottom wall of the second annular groove (12) has an opening (13), which penetrates the magnetohydrodynamic seal (3) radially along the long axis.

10. A magnetic fluid bellows combined sealing structure according to claim 8, characterized in that: The magnetic fluid seal (3) is fitted with a magnetic guide sleeve (14) with a clearance. The magnetic guide sleeve (14) is used to fix it on the long shaft. A third sealing ring is provided between the magnetic guide sleeve (14) and the long shaft. The second annular groove (12) is located on the side of the magnetic guide sleeve (14) close to the drive mechanism (4).

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