A sealing structure for a liquid metal bearing

Abstract

The present invention relates to the technical field of liquid metal bearings, in particular to a sealing structure of a liquid metal bearing. It includes a shaft, a shaft sleeve and an end cover. A circumferential radially protruding mounting boss is provided in the middle of the outer surface of the shaft. The lower part of the shaft is sleeved with the shaft sleeve, and the upper part of the shaft is sleeved with the end cover. Liquid metal is filled in the gap between the inner surface of the shaft sleeve and the outer surface of the shaft to form a liquid metal bearing structure. A bearing ring is arranged on the outer ring of the mounting boss. A first anti-wetting coating is provided on the side surface of the inner cavity of the end cover, a second anti-wetting coating is provided on the lower end surface of the end cover, a third anti-wetting coating is provided on the upper end surface of the shaft sleeve, and a fourth anti-wetting coating is provided on the upper and lower end surfaces of the bearing ring. In the present invention, an anti-wetting titanium oxide coating is generated in the area where the liquid metal needs to be sealed inside the liquid metal bearing, which not only solves the problem of weak bonding force between the coating and the substrate, reduces the risk of tube ignition and improves its long-term reliable operation, but also significantly reduces the equipment investment and operation cost, bringing obvious economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid metal bearings, and in particular to a sealing structure of a liquid metal bearing. Background Art

[0002] When the rotating anode of a CT tube rotates at a high speed during use, a large amount of heat is generated. The existing ball bearings used in CT tubes are difficult to dissipate the heat generated by high-speed rotation, resulting in unsatisfactory heat dissipation and affecting the service life of the X-ray tube.

[0003] To solve the heat dissipation problem, liquid metal bearings are used to replace ball bearings in CT tubes. In the prior art, the structural components of liquid metal bearings are mostly connected by screws, which makes it possible for the liquid metal sealed in the bearing gap to leak. During the operation of the CT tube, the anode rotates at a high speed, and the rotational speed of the liquid bearing supporting the anode reaches 10,000 revolutions per minute. The high pressure caused by the high rotational speed may also cause leakage of the liquid metal bearing. At the same time, the bearing will also be subjected to high temperature during operation, and the high temperature is also not conducive to the sealing performance of the liquid metal. Summary of the Invention

[0004] The present application aims at the above-mentioned shortcomings in the existing production technology, and provides a sealing structure for a liquid metal bearing, which can improve the sealing performance of the liquid metal in the liquid metal bearing, effectively reduce the risk of liquid metal overflow, increase the service time of the liquid metal bearing, and extend the working life of the CT tube.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A sealing structure for a liquid metal bearing, comprising a shaft, a shaft sleeve and an end cover. A circumferential radially protruding mounting boss is provided in the middle of the outer surface of the shaft. The lower part of the shaft is sleeved with the shaft sleeve, and the upper end surface of the shaft sleeve contacts the lower end surface of the mounting boss. The upper part of the shaft is sleeved with the end cover, and the lower end surface of the end cover contacts the upper end surface of the mounting boss. The gap between the inner surface of the shaft sleeve and the outer surface of the shaft is filled with liquid metal to form a liquid metal bearing structure. A bearing ring is provided on the outer ring of the mounting boss, and a plurality of fastening bolts are provided on the end cover. The plurality of fastening bolts pass through the bearing ring and are threadedly connected to the shaft sleeve through threads. A first anti-wetting coating is provided on the side surface of the inner cavity of the end cover, a fifth anti-wetting coating is provided on the surface of the shaft facing the first anti-wetting coating, a second anti-wetting coating is provided on the lower end surface of the end cover, a third anti-wetting coating is provided on the upper end surface of the shaft sleeve, and a fourth anti-wetting coating is provided on the upper and lower end surfaces of the bearing ring. The fourth anti-wetting coating covers the entire upper and lower end surfaces of the bearing ring.

[0007] Further, an expansion cavity is provided on the inner surface of the bearing ring, and the expansion cavity can accommodate the flow of liquid metal.

[0008] Further, an expansion groove is provided on the inner surface of the end cover, and the expansion groove can accommodate the liquid metal overflowing from the expansion cavity.

[0009] Further, the first anti-wetting coating, the second anti-wetting coating, the third anti-wetting coating, and the fourth anti-wetting coating are all coated with an anti-wetting substance at the set positions. The anti-wetting substance is titanium acetylacetonate or other substances with equivalent functions. Then, the bearing parts with the coatings are placed in a constant-temperature heating box, and the temperature is controlled at 200-400°C and maintained for 15-60 minutes, so that the titanium acetylacetonate undergoes physical evaporation and chemical reactions, thereby in-situ generating a titanium oxide coating in the set area.

[0010] Further, the thicknesses of the first anti-wetting coating, the second anti-wetting coating, the third anti-wetting coating, and the fourth anti-wetting coating are 0.2-1.5 µm.

[0011] Further, a plurality of bolt mounting holes penetrating up and down are provided at the positions on the bushing, the end cover, and the bearing ring where the fastening bolts are connected. A plurality of fastening bolts are correspondingly arranged in the plurality of bolt mounting holes one by one. A plurality of exhaust holes are provided on the side surface of the bearing ring, and the plurality of exhaust holes are correspondingly communicated with the plurality of bolt mounting holes one by one.

[0012] Further, a plurality of end cover bolt holes are provided on the upper end surface of the end cover, and the plurality of end cover bolt holes are evenly distributed along the circumferential direction of the end cover. A plurality of end cover exhaust holes are provided on the side surface of the end cover, and the plurality of end cover exhaust holes are correspondingly communicated with the plurality of end cover bolt holes one by one.

[0013] Further, a cathode shaft section is welded to the upper end of the shaft, and cooling holes are axially provided inside the shaft and the cathode shaft section.

[0014] The beneficial effects of the present invention are as follows:

[0015] The present invention generates an anti-wetting titanium oxide coating in the area inside the liquid metal bearing that needs to seal the liquid metal, which not only solves the problem of weak bonding force between the coating and the substrate, reduces the risk of tube arcing, and improves its long-term reliable operation, but also significantly reduces the equipment investment and operation costs, bringing obvious economic benefits; the sealing structure of the present invention can improve the sealing performance of the liquid metal in the liquid metal bearing, effectively reduce the risk of liquid metal overflow, increase the service time of the liquid metal bearing, and extend the working life of the CT tube. Description of the Drawings

[0016] Figure 1 It is a three-dimensional structure diagram of the present invention.

[0017] Figure 2 It is a half-sectional view of the present invention.

[0018] Among them: 1. shaft; 2. sleeve; 3. end cover; 4. bearing ring; 5. fastening bolt; 6. mounting boss; 7. cathode shaft segment; 8. cooling hole; 9. exhaust hole; 10. bolt mounting hole; 11. expansion chamber; 12. expansion slot; 13. end cover bolt hole; 14. end cover exhaust hole; 15. first anti-wetting coating; 16. second anti-wetting coating; 17. third anti-wetting coating. DETAILED DESCRIPTION

[0019] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0020] like Figure 1 and Figure 2 As shown, a sealing structure for a liquid metal bearing comprises a shaft 1, a sleeve 2, and an end cap 3. A radially protruding mounting boss 6 is provided in the middle of the outer surface of the shaft 1. The lower portion of the shaft 1 is sleeved with the sleeve 2, with the upper end surface of the sleeve 2 contacting the lower end surface of the mounting boss 6. The upper portion of the shaft 1 is sleeved with the end cap 3, with the lower end surface of the end cap 3 contacting the upper end surface of the mounting boss 6. The mounting boss 6 provides axial positioning for the sleeve 2 and end cap 3.

[0021] like Figure 2 As shown, the gap between the inner surface of the sleeve 2 and the outer surface of the shaft 1 is filled with liquid metal to form a liquid metal bearing structure.

[0022] like Figure 1 and Figure 2 As shown, a bearing ring 4 is provided on the outer ring of the mounting boss 6, and a plurality of fastening bolts 5 are provided on the end cover 3. The fastening bolts 5 are evenly distributed along the circumference of the end cover 3. The fastening bolts 5 pass through the bearing ring 4 and are connected to the shaft sleeve 2 through threads.

[0023] like Figure 2 As shown, the inner surface of the bearing ring 4 is provided with an expansion cavity 11, which can accommodate the flow of liquid metal. The inner surface of the end cover 3 is provided with an expansion groove 12, which can accommodate the liquid metal overflowing from the expansion cavity 11.

[0024] To prevent liquid metal from spilling, Figure 2 As shown, a first anti-wetting coating 15 is applied to the inner side of the end cap 3, located below the expansion slot 12. A fifth anti-wetting coating is applied to the surface of the shaft 1 facing the first anti-wetting coating 15. A second anti-wetting coating 16 is applied to the lower end surface of the end cap 3, and a third anti-wetting coating 17 is applied to the upper end surface of the sleeve 2. A fourth anti-wetting coating is applied to the upper and lower end surfaces of the bearing ring 4, covering the entire upper and lower end surfaces of the bearing ring 4.

[0025] The first anti-wetting coating 15, the second anti-wetting coating 16, the third anti-wetting coating 17, the fourth anti-wetting coating, and the fifth anti-wetting coating are all coated with an anti-wetting substance at the set positions. The anti-wetting substance is titanium acetylacetonate or other substances with equivalent functions. Then, the bearing parts with the coated coatings are placed in a constant-temperature heating box, and the temperature is controlled at 200 - 400 °C and maintained for a period of time, which is 15 - 60 minutes, so that the titanium acetylacetonate undergoes physical evaporation and chemical reactions, thereby in-situ generating a titanium oxide coating in the set area. Since liquid metal cannot wet the titanium oxide coating, the reliability of liquid metal sealing is effectively improved.

[0026] Meanwhile, under the combined action of thermal diffusion and concentration gradient, the effective components of the coating molecules penetrate into the matrix material inward and form a reliable metallurgical connection, ensuring that the coating has high adhesion and lasting stability. Control the constant-temperature heating box to slowly cool the parts in the furnace to room temperature and then take them out. Finally, complete the assembly of the parts and the injection of liquid metal. The part assembly sequence is: brush a certain amount of liquid metal on the shaft 1, fix the shaft sleeve 2, install the bearing ring 4, put in the shaft 1, install the end cover 3, and finally tighten the fastening bolt 5.

[0027] The thicknesses of the first anti-wetting coating 15, the second anti-wetting coating 16, the third anti-wetting coating 17, the fourth anti-wetting coating, and the fifth anti-wetting coating are generally 0.2 - 1.5 μm.

[0028] As Figure 1 and Figure 2 shown, multiple bolt mounting holes 10 penetrating up and down are provided at the positions on the shaft sleeve 2, the end cover 3, and the bearing ring 4 where the fastening bolt 5 is connected, and multiple fastening bolts 5 are correspondingly arranged in the multiple bolt mounting holes 10 one by one. Multiple exhaust holes 9 are provided on the side of the bearing ring 4, and the multiple exhaust holes 9 are correspondingly connected to the multiple bolt mounting holes 10 one by one.

[0029] As Figure 1 shown, multiple end cover bolt holes 13 are provided on the upper end face of the end cover 3, and the multiple end cover bolt holes 13 are evenly distributed along the circumferential direction of the end cover 3. Multiple end cover exhaust holes 14 are provided on the side of the end cover 3, and the multiple end cover exhaust holes 14 are correspondingly connected to the multiple end cover bolt holes 13 one by one.

[0030] As Figure 2 shown, a cathode shaft section 7 is welded to the upper end of the shaft 1, and cooling holes 8 are axially provided inside the shaft 1 and the cathode shaft section 7. A cooling medium can be filled in the cooling holes 8, and the heat generated during the operation of the CT tube can be quickly conducted into the cooling holes 8 at the center of the shaft 1 and the cathode shaft section 7, and the heat is taken away by the cooling medium in the cooling holes 8.

[0031] The present invention is based on element diffusion and chemical reaction, and uses "in-situ growth" technology to generate an anti-wetting coating in the area inside the liquid metal bearing that needs to seal the liquid metal. This not only solves the problem of weak bonding between the coating and the substrate, reduces the risk of tube ignition and improves its long-term reliable operation, but also significantly reduces equipment investment and operating costs, bringing significant economic benefits.

[0032] The present invention can improve the sealing performance of liquid metal in the liquid metal bearing, effectively reduce the risk of liquid metal overflow, increase the service life of the liquid metal bearing, and extend the service life of the CT tube.

[0033] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any modifications may be made within the scope of protection of the present invention.

Claims

1. A sealing structure for a liquid metal bearing, comprising a shaft (1), a bearing sleeve (2) and an end cover (3), characterized in that: A mounting boss (6) protruding radially is provided in the middle of the outer surface of the shaft (1). A bushing (2) is sleeved on the lower part of the shaft (1), and the upper end face of the bushing (2) contacts the lower end face of the mounting boss (6). An end cover (3) is sleeved on the upper part of the shaft (1), and the lower end face of the end cover (3) contacts the upper end face of the mounting boss (6). Liquid metal is filled in the gap between the inner surface of the bushing (2) and the outer surface of the shaft (1) to form a liquid metal bearing structure. A bearing ring (4) is provided on the outer ring of the mounting boss (6). A plurality of fastening bolts (5) are provided on the end cover (3). After passing through the bearing ring (4), the plurality of fastening bolts (5) are threadedly connected to the bushing (2). A first anti-wetting coating (15) is provided on the inner side surface of the cavity of the end cover (3). A fifth anti-wetting coating is provided on the surface of the shaft (1) facing the first anti-wetting coating (15). A second anti-wetting coating (16) is provided on the lower end face of the end cover (3). A third anti-wetting coating (17) is provided on the upper end face of the bushing (2). Fourth anti-wetting coatings are provided on the upper and lower end faces of the bearing ring (4), and the fourth anti-wetting coatings cover the entire upper and lower end faces of the bearing ring (4). A plurality of bolt mounting holes (10) penetrating up and down are provided at the positions where the bushing (2), the end cover (3) and the bearing ring (4) are connected with the fastening bolts (5). The plurality of fastening bolts (5) are correspondingly arranged in the plurality of bolt mounting holes (10). A plurality of exhaust holes (9) are provided on the side surface of the bearing ring (4), and the plurality of exhaust holes (9) are correspondingly communicated with the plurality of bolt mounting holes (10). A plurality of end cover bolt holes (13) are provided on the upper end face of the end cover (3), and the plurality of end cover bolt holes (13) are evenly distributed along the circumferential direction of the end cover (3). A plurality of end cover exhaust holes (14) are provided on the side surface of the end cover (3), and the plurality of end cover exhaust holes (14) are correspondingly communicated with the plurality of end cover bolt holes (13).

2. The sealing structure of a liquid metal bearing according to claim 1, characterized in that: An expansion cavity (11) is provided on the inner surface of the bearing ring (4), and the expansion cavity (11) can accommodate the flow of liquid metal.

3. The sealing structure of a liquid metal bearing according to claim 2, wherein: An expansion groove (12) is provided on the inner surface of the end cover (3), and the expansion groove (12) can accommodate the liquid metal overflowing from the expansion cavity (11).

4. The sealing structure of a liquid metal bearing according to claim 1, wherein: The first anti-wetting coating (15), the second anti-wetting coating (16), the third anti-wetting coating (17), the fourth anti-wetting coating and the fifth anti-wetting coating are all coated with anti-wetting substances at the set positions. The anti-wetting substance is titanium acetylacetonate. Then, the bearing parts coated with the coatings are placed in a constant temperature heating box, and the temperature is controlled at 200 - 400 °C and maintained for 15 - 60 minutes, so that titanium acetylacetonate undergoes physical evaporation and chemical reactions, thereby in-situ generating titanium oxide coatings in the set areas.

5. The sealing structure of a liquid metal bearing according to claim 4, characterized in that: The thicknesses of the first anti-wetting coating (15), the second anti-wetting coating (16), the third anti-wetting coating (17) and the fourth anti-wetting coating are 0.2 - 1.5 μm.

6. The sealing structure of a liquid metal bearing according to claim 1, characterized in that: A cathode shaft section (7) is welded to the upper end of the shaft (1), and cooling holes (8) are axially provided in the shaft (1) and the cathode shaft section (7).

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