An inner circulating end face seal combined structure liquid metal bearing

Abstract

The application relates to the technical field of CT tube, and discloses a liquid metal bearing with an inner circulation end face sealing combined structure, which comprises a CT tube, the CT tube comprises a shell, the inside of the shell is provided with a cathode, the inside of the shell is provided with an anode target surface, the right end of the shell is provided with a support shaft system, the support shaft system comprises a bearing sleeve, the outer wall of the bearing sleeve is welded at the right end of the CT tube, the right end of the bearing sleeve is rotationally connected with a shaft, the outer wall of the shaft is provided with a shaft shoulder, the right end of the bearing sleeve is provided with a shaft shoulder flared mouth, the right end of the shaft shoulder is provided with a shaft cover, the left end of the shaft cover is fixedly connected at the right end of the bearing sleeve, and the outer wall of the shaft is provided with a radial spiral groove. In the application, the end face sealing combined structure is improved, so that the liquid metal used for bearing and lubricating the shaft system can be prevented from leaking under extreme conditions such as high rotation speed, high temperature and vacuum, and the sealing performance is good during use.

Description

Technical Field

[0001] This invention relates to the field of CT tube technology, and in particular to a liquid metal bearing with an internal circulation end face sealing combination structure. Background Technology

[0002] The CT tube is the core component of a CT scanner that generates X-rays. The working principle of the CT tube is as follows: high-speed electrons carrying negative charges interact with the positive electric field of the target atom nucleus and the negative electric field outside the nucleus. The main interaction modes are elastic collision and inelastic collision.

[0003] To ensure lubrication between internal components of a CT tube, liquid metal is typically used as a lubricant due to its excellent fluidity, thermal conductivity, and thermal stability. However, using liquid metal as a lubricant places high demands on the sealing performance of the device. Poor sealing can lead to liquid metal leakage, damaging the CT tube and reducing the quality of CT images. On the other hand, loss of the lubricating medium can cause bearing slippage and wear, affecting its performance. Currently, sealing technology for liquid metal in CT tubes is not mature enough. Therefore, the end-face sealing performance can be further improved by optimizing and redesigning this sealing technology. Summary of the Invention

[0004] To overcome the above deficiencies, this invention provides a liquid metal bearing with an internal circulation end face sealing combination structure, which aims to improve the problem mentioned in the prior art that "the existing CT tube setup still has defects and the sealing performance needs to be further improved".

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a liquid metal bearing with an internal circulation end-face sealing combination structure, comprising a CT tube, the CT tube comprising a housing, a cathode disposed inside the housing, an anode target disposed inside the housing, a support shaft system disposed at the right end of the housing, the support shaft system comprising a bearing sleeve, the outer wall of the bearing sleeve being welded to the right end of the CT tube, a shaft rotatably connected to the right end of the bearing sleeve, a shoulder disposed on the outer wall of the shaft, a shoulder flare disposed at the right end of the bearing sleeve, a shaft cover disposed at the right end of the shoulder, the left end of the shaft cover being fixedly connected to the right end of the bearing sleeve, a radial helical groove disposed on the outer wall of the shaft, a shoulder end-face helical groove disposed at the left end of the shoulder, a reflux groove disposed on the outer wall of the shaft near the right end of the shoulder, a circulation hole disposed at the left end of the shaft, an outlet hole disposed on the outer wall of the shaft, the circulation hole, the outlet hole, and the reflux groove being interconnected, and a shaft cover helical groove disposed at the left end of the shaft cover.

[0006] As a further description of the above technical solution: The inner wall of the shaft cover is provided with a labyrinth sealing structure, and the reflux groove is located in the first sealing cavity of the labyrinth sealing structure.

[0007] As a further description of the above technical solution: The gap h1 between the shoulder and the bottom surface of the shoulder flare on both sides and the end face of the cover is in the range of 10~50μm.

[0008] As a further description of the above technical solution: The radial spiral groove is configured as a herringbone structure.

[0009] As a further description of the above technical solution: Both the spiral groove on the shoulder end face and the spiral groove on the shaft cover are herringbone grooves, and one cycle of the herringbone groove consists of one groove and one step.

[0010] As a further description of the above technical solution: The cross-section of the groove is a combination of one or more of the following shapes: rectangular, arc-shaped, trapezoidal, and triangular.

[0011] As a further description of the above technical solution: The bearing sleeve and the shaft cover are fixedly connected by bolts.

[0012] As a further description of the above technical solution: The outer wall of the shaft is provided with a coating layer.

[0013] As a further description of the above technical solution: When the support shaft system rotates, the shaft is fixed, and the rotation of the bearing sleeve drives the liquid metal to generate a dynamic pressure effect to achieve lubrication.

[0014] As a further description of the above technical solution: When the end face of the support shaft is sealed, the shaft shoulder is fixed, and the flared rotation of the shaft cover and bearing sleeve drives the liquid metal to generate a dynamic pressure effect to achieve lubrication and sealing.

[0015] The present invention has the following beneficial effects: In this invention, by improving the end-face sealing assembly structure, it is possible to prevent leakage of liquid metal used for shaft bearing and lubrication under extreme conditions such as high speed, high temperature and vacuum. It has good sealing performance during use, better prevents leakage of liquid metal, and enables liquid metal to circulate back.

[0016] In this invention, by setting a coating layer on the outer wall of the shaft, the liquid metal can flow better on the outer wall of the shaft, thereby improving the lubrication effect and making the overall device more stable during operation. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of the CT tube in this invention; Figure 2 This is a three-dimensional structural diagram of the rotating anode shaft in this invention; Figure 3 This is a three-dimensional structural diagram of the support shaft in this invention; Figure 4 This is a three-dimensional cross-sectional view of the support shaft in this invention; Figure 5 This is a three-dimensional structural diagram of the shaft cover in this invention; Figure 6 This is a schematic diagram of the end face structure of the spiral groove on the shoulder end face of the present invention. Figure 7 This is a cross-sectional schematic diagram of the coating layer in this invention; Figure 8 This is a cross-sectional schematic diagram of the herringbone spiral groove on the end face in this invention.

[0018] Legend: 1. CT tube; 11. Cathode; 12. Anode target surface; 13. Housing; 14. Support shaft system; 21. Bearing sleeve; 22. Shaft; 23. Shaft cover; 24. Shaft shoulder; 31. Radial helical groove; 32. Helical groove on the end face of the shaft shoulder; 33. Reflux groove; 34. Circulation hole; 35. Outlet hole; 41. Coating layer; 51. Helical groove on the shaft cover; 52. Labyrinth seal structure; 61. Groove; 62. Step. 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] Reference Figure 1 - Figure 4One embodiment of the present invention provides a liquid metal bearing with an internal circulation end-face sealing assembly, comprising a CT tube 1. The CT tube 1 includes a housing 13 for protecting the overall device. A cathode 11 is disposed inside the housing 13. An anode target 12 with a heat sink sleeve is disposed inside the housing 13. A support shaft system 14 is disposed at the right end of the housing 13. The support shaft system 14 includes a bearing sleeve 21 for enclosing a shaft 22. The outer wall of the bearing sleeve 21 is welded to the right end of the CT tube 1. The right end of the bearing sleeve 21 is rotatably connected to the shaft 22. The outer wall of the shaft 22 is provided with a shoulder. 24. A shoulder flare is provided at the right end of the bearing sleeve 21. The left side of the shoulder 24 abuts against the shoulder flare. A shaft cover 23 is provided at the right end of the shoulder 24. The left end of the shaft cover 23 is fixedly connected to the right end of the bearing sleeve 21. The shaft cover 23 and the bearing sleeve 21 are fixedly connected to achieve axial positioning of the shaft 22 within the bearing sleeve 21. A radial helical groove 31 is provided on the outer wall of the shaft 22. A shoulder end face helical groove 32 is provided at the left end of the shoulder 24. The shoulder end face helical groove 32 is located on the shoulder end face abutting against the shoulder flare. A return groove 33 is provided on the outer wall of the shaft 22 near the right end of the shoulder 24. The gap between the shaft 22 and the bearing sleeve 21 is filled with liquid metal, which is a gallium indium tin liquid alloy. A circulation hole 34 is provided at the left end of the shaft 22, and an outlet hole 35 is provided on the outer wall of the shaft 22. The circulation hole 34, the outlet hole 35, and the return groove 33 are interconnected. A shaft cover spiral groove 51 is provided at the left end of the shaft cover 23. When the support shaft system 14 rotates, the shaft 22 is fixed, and the rotation of the bearing sleeve 21 drives the liquid metal to generate a dynamic pressure effect to achieve lubrication. The liquid metal is discharged from the end face and side face of the shaft 22 through the outlet hole 35 and the circulation hole 34 into the gap between the shaft 22 and the bearing sleeve 21. Under the guidance of the radial spiral groove 31, the liquid metal is pushed to the shoulder 24. Then, under the combined action of the spiral groove 32 on the end face of the shoulder and the spiral groove 51 on the shaft cover, the liquid metal crosses the shoulder 24 and enters the return groove 33. The liquid metal in the return groove 33 flows back to the axial return hole to achieve flow circulation. When the end face of the support shaft system 14 is sealed, the shoulder 24 is fixed, and the shaft cover 23 and the bearing sleeve flare rotate to drive the liquid metal to generate a dynamic pressure effect to achieve lubrication and sealing. This setting can ensure that the liquid metal does not leave the inside of the device and can also ensure that the liquid metal can provide lubrication for the device.

[0021] Reference Figure 2 , Figure 3 , Figure 5 and Figure 8 The inner wall of the shaft cover 23 is provided with a labyrinth seal structure 52 to block liquid metal. The return groove 33 is located in the first sealing cavity of the labyrinth seal structure 52. The gap h1 between the shaft shoulder 24 and the bottom surface of the shaft shoulder flare on both sides and the end face of the shaft cover 23 is 10~50μm. In order to ensure that the outflowing liquid metal can be completely returned by the return groove 33, the return groove 33 should be completely in the first sealing cavity of the labyrinth seal structure 52.

[0022] Reference Figure 6 The radial spiral groove 31 is set as a herringbone structure. The spiral groove 32 on the shoulder end face and the spiral groove 51 on the shaft cover are both herringbone grooves. One cycle of the herringbone groove consists of a groove 61 and a step 62. The groove 61 is laser-processed. The appropriate range of the groove depth h2 is 5~30μm. When the groove depth h2 is less than 5μm, the dynamic pressure effect of the liquid metal will be weakened, which will significantly reduce the load-bearing capacity and other properties. When the groove depth h2 is greater than 30μm, it is relatively difficult for the liquid metal to cross the herringbone groove step, and the performance will also be affected.

[0023] Reference Figure 6 The cross-section of groove 61 is a combination of one or more of the following shapes: rectangular, arc-shaped, trapezoidal, and triangular. The suitable range for the helix angle β is 30° to 70°. When the helix angle β is less than 30°, the wedge effect of hydrodynamic lubrication is not obvious, and the resulting sliding bearing pressure is relatively small. When the helix angle β is greater than 70°, the frictional torque generated by the rotation of the liquid metal bearing will increase, resulting in a higher temperature rise and affecting the bearing performance. This invention defines a herringbone groove cycle as consisting of a groove 61 and a step 62, and defines the groove width ratio δ as a herringbone groove based on the base circle radius rm. The width of the groove is the proportion of the herringbone groove's periodic width. The appropriate range for the groove width ratio δ is 0.3 to 0.7. If it exceeds this range, the liquid metal bearing will have poor sealing performance. The number of herringbone grooves can be increased if the processing conditions and processing costs allow. The bearing sleeve 21 and the shaft cover 23 are fixedly connected by bolts. The outer wall of the shaft 22 is provided with a coating layer 41, and the coating material is TiN or TiNAl. Liquid metal has poor wettability on the surface of TiN or TiNAl. This can be used to allow the liquid metal to flow better into the return groove 33, thereby enhancing the sealing effect of the sealing structure of the present invention.

[0024] Working principle: When the equipment starts working, the liquid metal will also flow inside the device due to centrifugal force. The liquid metal will flow along the radial spiral groove 31 in the gap between the shaft 22 and the bearing sleeve 21. When the liquid metal flows to the left end of the shaft shoulder 24, it will be affected by the spiral groove 32 on the end face of the shaft shoulder and the spiral groove 51 on the shaft cover. Under the combined action, the liquid metal will cross the shaft shoulder 24 and enter the return groove 33, and flow back to the location of the outlet hole 35 and the circulation hole 34. In this way, the liquid metal will continuously circulate inside the device.

[0025] This utility model can also be used in applications such as end face sealing of liquid metal bearings in communication, navigation, remote sensing and telemetry, wind power generation equipment, air traffic control radar, port navigation radar, weather radar, satellite communication, medical CT and airport security scanning equipment, semiconductor manufacturing equipment and industrial manufacturing equipment.

[0026] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A liquid metal bearing with an internal circulation end-face sealing assembly structure, comprising a CT ball tube (1), characterized in that: The CT tube (1) includes a housing (13), inside which a cathode (11) is disposed, and inside which an anode target surface (12) is disposed. A support shaft system (14) is disposed at the right end of the housing (13), and the support shaft system (14) includes a bearing sleeve (21). The outer wall of the bearing sleeve (21) is welded to the right end of the CT tube (1). A shaft (22) is rotatably connected to the right end of the bearing sleeve (21). A shoulder (24) is disposed on the outer wall of the shaft (22). A shoulder flare is disposed at the right end of the bearing sleeve (21). A shaft cover (23) is disposed at the right end of the shoulder (24). The left end of the shaft cover (23) is fixedly connected to the bearing sleeve (21). At the right end of the shaft (22), the outer wall of the shaft (22) is provided with a radial spiral groove (31), the left end of the shaft shoulder (24) is provided with a shaft shoulder end face spiral groove (32), the outer wall of the shaft (22) near the right end of the shaft shoulder (24) is provided with a return groove (33), the left end of the shaft (22) is provided with a circulation hole (34), the outer wall of the shaft (22) is provided with an outlet hole (35), the circulation hole (34), the outlet hole (35) and the return groove (33) are interconnected, the left end of the shaft cover (23) is provided with a shaft cover spiral groove (51); the inner wall of the shaft cover (23) is provided with a labyrinth seal structure (52), and the return groove (33) is located in the first sealing cavity of the labyrinth seal structure (52); When the support shaft system (14) rotates, the shaft (22) is fixed, and the bearing sleeve (21) rotates to drive the liquid metal to generate a dynamic pressure effect to achieve lubrication; When the end face of the support shaft system (14) is sealed, the shaft shoulder (24) is fixed, and the shaft cover (23) and the bearing sleeve rotate to drive the liquid metal to generate a dynamic pressure effect to achieve lubrication and sealing.

2. The liquid metal bearing with an internal circulation end face sealing combination structure according to claim 1, characterized in that: The gap h1 between the shoulder (24) and the bottom surface of the shoulder flare on both sides and the end face of the cover (23) is in the range of 10~50μm.

3. The liquid metal bearing with an internal circulation end face sealing combination structure according to claim 1, characterized in that: The radial spiral groove (31) is configured as a herringbone structure.

4. The liquid metal bearing with an internal circulation end face sealing combination structure according to claim 1, characterized in that: The spiral groove (32) on the shoulder end face and the spiral groove (51) on the shaft cover are both herringbone grooves. One cycle of the herringbone groove consists of a groove (61) and a step (62).

5. A liquid metal bearing with an internal circulation end face sealing combination structure according to claim 1, characterized in that: The cross-section of the groove (61) is a combination of one or more of the following cross-sections: rectangular, arc-shaped, trapezoidal, and triangular.

6. The liquid metal bearing with an internal circulation end face sealing combination structure according to claim 1, characterized in that: The bearing sleeve (21) and the shaft cover (23) are fixedly connected by bolts.

7. The liquid metal bearing with an internal circulation end face sealing combination structure according to claim 1, characterized in that: The outer wall of the shaft (22) is provided with a coating layer (41).

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