Sealing structure of liquid metal bearing

Abstract

The invention relates to the technical field of liquid metal bearings, in particular to a sealing structure of a liquid metal bearing. The bearing comprises a shaft, a shaft sleeve and an end cover, a circle of radially protruding mounting boss is arranged in the middle of the outer surface of the shaft, the lower portion of the shaft is sleeved with the shaft sleeve, the upper portion of the shaft is sleeved with the end cover, and a 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 first anti-infiltration coating is arranged on the side face of an inner cavity of the end cover, a second anti-infiltration coating is arranged on the lower end face of the end cover, a third anti-infiltration coating is arranged on the upper end face of the shaft sleeve, and fourth anti-infiltration coatings are arranged on the upper end face and the lower end face of the bearing ring. According to the method, the anti-infiltration titanium oxide coating is generated in the area, where liquid metal needs to be sealed, in the liquid metal bearing, the problem that the binding force between the coating and a base body is weak is solved, the sparking risk of a bulb tube is reduced, long-term reliable operation of the bulb tube is improved, the equipment investment and operation cost are remarkably reduced, and obvious economic benefits are brought.

Description

Technical Field

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

[0002] The rotating anode of the CT tube generates a lot of heat when it is in use due to high-speed rotation. The ball bearings used in existing CT tubes are difficult to dissipate the heat generated by high-speed rotation, resulting in unsatisfactory heat dissipation and shortening the service life of the X-ray tube.

[0003] In order to solve the problem of heat dissipation, CT tubes use liquid metal bearings instead of ball bearings. In the prior art, the structural parts 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 high speed, and the liquid bearing supporting the anode rotates at a speed of 10,000 rpm. The high pressure caused by the high speed may also cause leakage of the liquid metal bearing. At the same time, the bearing will also be exposed to high temperature during operation, which is not conducive to the sealing performance of the liquid metal. Summary of the invention

[0004] In view of the shortcomings in the above-mentioned existing production technology, the present application provides a sealing structure of 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 life 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: A sealing structure of a liquid metal bearing comprises a shaft, a sleeve and an end cover, wherein a circle of radially protruding mounting bosses is arranged in the middle of the outer surface of the shaft, the lower part of the shaft is sleeved with the sleeve, the upper end face of the sleeve contacts the lower end face of the mounting bosses, the upper part of the shaft is sleeved with the end cover, the lower end face of the end cover contacts the upper end face of the mounting bosses, and the gap between the inner surface of the sleeve and the outer surface of the shaft is filled with liquid metal to form a liquid metal bearing structure; a bearing ring is arranged on the outer ring of the mounting boss, a plurality of fastening bolts are arranged on the end cover, and the plurality of fastening bolts pass through the bearing ring and are connected to the sleeve by threads; a first anti-wetting coating is arranged on the side surface of the inner cavity of the end cover, a fifth anti-wetting coating is arranged on the surface of the upper part of the shaft facing the first anti-wetting coating, a second anti-wetting coating is arranged on the lower end face of the end cover, a third anti-wetting coating is arranged on the upper end face of the sleeve, and a fourth anti-wetting coating is arranged on the upper and lower end faces of the bearing ring, and the fourth anti-wetting coating covers the entire upper and lower end faces of the bearing ring.

[0006] Furthermore, an expansion cavity is provided on the inner surface of the bearing ring, and the expansion cavity can accommodate the flow of liquid metal.

[0007] Furthermore, an expansion groove is provided on the inner surface of the end cover, and the expansion groove can accommodate liquid metal overflowing from the expansion cavity.

[0008] Furthermore, 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 position, and the anti-wetting substance is titanium acetylacetonate or other equivalent substances. Then the bearing parts coated with the coating are placed in a constant temperature heating box, and the temperature is controlled at 200~400℃ and maintained for 15~60 minutes, so that the titanium acetylacetonate undergoes physical evaporation and chemical reaction, thereby generating a titanium oxide coating in situ in the set area.

[0009] Furthermore, the thickness of the first anti-wetting coating, the second anti-wetting coating, the third anti-wetting coating and the fourth anti-wetting coating is 0.2-1.5 um.

[0010] Furthermore, a plurality of bolt mounting holes extending vertically through the shaft sleeve, the end cover and the bearing ring are provided at positions where the fastening bolts are connected, and a plurality of fastening bolts are arranged in the plurality of bolt mounting holes in a one-to-one correspondence. A plurality of exhaust holes are provided on the side of the bearing ring, and the plurality of exhaust holes are connected in a one-to-one correspondence with the plurality of bolt mounting holes.

[0011] Furthermore, a plurality of end cover bolt holes are arranged 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 arranged on the side surface of the end cover, and the plurality of end cover exhaust holes and the plurality of end cover bolt holes are connected one by one.

[0012] Furthermore, a cathode shaft segment is welded to the upper end of the shaft, and cooling holes are arranged in the shaft and the cathode shaft segment along the axial direction.

[0013] The beneficial effects of the present invention are as follows: The present invention generates an anti-wetting titanium oxide coating 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 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 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 life of the liquid metal bearing, and extend the working life of the CT tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a three-dimensional structural diagram of the present invention.

[0015] Figure 2 It is a half-section view of the present invention.

[0016] Among them: 1. shaft; 2. sleeve; 3. end cover; 4. bearing ring; 5. fastening bolts; 6. mounting boss; 7. cathode shaft segment; 8. cooling hole; 9. exhaust hole; 10. bolt mounting hole; 11. expansion cavity; 12. expansion groove; 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

[0017] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0018] like Figure 1 and Figure 2 As shown, a sealing structure of a liquid metal bearing includes a shaft 1, a sleeve 2 and an end cover 3, and a circle of radially protruding mounting bosses 6 is arranged in the middle of the outer surface of the shaft 1. The lower part of the shaft 1 is sleeved with the sleeve 2, and the upper end surface of the sleeve 2 contacts the lower end surface of the mounting boss 6. The upper part of the shaft 1 is sleeved with the end cover 3, and the lower end surface of the end cover 3 contacts the upper end surface of the mounting boss 6. The mounting boss 6 plays a role in axial positioning of the sleeve 2 and the end cover 3.

[0019] 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.

[0020] like Figure 1 and Figure 2 As shown, a bearing ring 4 is arranged on the outer ring of the mounting boss 6, and a plurality of fastening bolts 5 are arranged on the end cover 3, and the plurality of fastening bolts 5 are evenly distributed along the circumference of the end cover 3. The plurality of fastening bolts 5 pass through the bearing ring 4 and are connected to the shaft sleeve 2 by threads.

[0021] 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.

[0022] To prevent liquid metal from spilling, Figure 2 As shown, a first anti-wetting coating 15 is provided on the inner cavity side of the end cover 3, and the first anti-wetting coating 15 is located below the expansion groove 12. A fifth anti-wetting coating is provided on the surface of the first anti-wetting coating 15 on the shaft 1. A second anti-wetting coating 16 is provided on the lower end surface of the end cover 3, and a third anti-wetting coating 17 is provided on the upper end surface of the sleeve 2. A fourth anti-wetting coating is provided on the upper and lower end surfaces of the bearing ring 4, and the fourth anti-wetting coating covers the entire upper and lower end surfaces of the bearing ring 4.

[0023] 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, and the anti-wetting substances are titanium acetylacetonate or other equivalent substances, and 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 a period of time, which is 15-60 minutes, so that the titanium acetylacetonate undergoes physical evaporation and chemical reaction, thereby generating a titanium oxide coating in situ in the set area. Since liquid metal cannot infiltrate the titanium oxide coating, the reliability of the liquid metal seal is effectively improved.

[0024] At the same time, under the combined effect of thermal diffusion and concentration gradient, the effective components of the coating molecules penetrate into the matrix material and form a reliable metallurgical connection, ensuring that the coating has high adhesion and long-term stability. Control the constant temperature heating box to slowly cool the parts to room temperature with the furnace before taking them out. Finally, complete the assembly of the parts and the injection of liquid metal. The order of parts assembly is: brush a certain amount of liquid metal on the shaft 1, fix the sleeve 2, install the bearing ring 4, put in the shaft 1, install the end cover 3, and finally tighten the fastening bolts 5.

[0025] The thickness 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 is generally 0.2-1.5 um.

[0026] like Figure 1 and Figure 2 As shown, a plurality of bolt mounting holes 10 are provided at the positions where the fastening bolts 5 are connected on the shaft sleeve 2, the end cover 3 and the bearing ring 4, and a plurality of fastening bolts 5 are provided in the plurality of bolt mounting holes 10 in a one-to-one correspondence. A plurality of exhaust holes 9 are provided on the side of the bearing ring 4, and the plurality of exhaust holes 9 are connected in a one-to-one correspondence with the plurality of bolt mounting holes 10.

[0027] like Figure 1 As shown, a plurality of end cover bolt holes 13 are arranged on the upper end surface of the end cover 3, and the plurality of end cover bolt holes 13 are evenly distributed along the circumference of the end cover 3. A plurality of end cover exhaust holes 14 are arranged on the side surface of the end cover 3, and the plurality of end cover exhaust holes 14 are connected to the plurality of end cover bolt holes 13 in a one-to-one correspondence.

[0028] like Figure 2 As shown, a cathode shaft segment 7 is welded to the upper end of the shaft 1, and a cooling hole 8 is axially arranged in the shaft 1 and the cathode shaft segment 7. A cooling medium can be filled into the cooling hole 8. The heat generated when the CT tube is working can be quickly conducted to the cooling hole 8 at the center of the shaft 1 and the cathode shaft segment 7, and the heat is taken away by the cooling medium in the cooling hole 8.

[0029] The present invention is based on element diffusion and chemical reaction, "in-situ growth" technology, and generates an anti-wetting coating in the area inside the liquid metal bearing where the liquid metal needs to be sealed. It 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 obvious economic benefits.

[0030] 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.

[0031] 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 form of modification may be made within the scope of protection of the present invention.

Claims

1. A sealing structure of a liquid metal bearing, comprising a shaft (1), a shaft sleeve (2) and an end cover (3), characterized in that: A circle of radially protruding mounting bosses (6) is arranged in the middle of the outer surface of the shaft (1); the lower part of the shaft (1) is sleeved with the shaft sleeve (2); the upper end surface of the shaft sleeve (2) contacts the lower end surface of the mounting boss (6); the upper part of the shaft (1) is sleeved with the end cover (3); the lower end surface of the end cover (3) contacts the upper end surface of the mounting boss (6); liquid metal is filled in the gap between the inner surface of the shaft sleeve (2) and the outer surface of the shaft (1) to form a liquid metal bearing structure; a bearing ring (4) is arranged on the outer ring of the mounting boss (6); a plurality of fastening bolts (5) are arranged on the end cover (3); ), a plurality of fastening bolts (5) pass through the bearing ring (4) and are then connected to the shaft sleeve (2) through threads; a first anti-wetting coating (15) is provided on the inner cavity side 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 surface of the end cover (3), a third anti-wetting coating (17) is provided on the upper end surface of the shaft sleeve (2), and a fourth anti-wetting coating is provided on the upper and lower end surfaces of the bearing ring (4), wherein the fourth anti-wetting coating covers the entire upper and lower end surfaces of the bearing ring (4).

2. A 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) is capable of accommodating the flow of liquid metal.

3. A sealing structure of a liquid metal bearing as claimed in claim 2, characterized in that: An expansion groove (12) is provided on the inner surface of the end cover (3), and the expansion groove (12) is capable of accommodating liquid metal overflowing from the expansion cavity (11).

4. A sealing structure for a liquid metal bearing as claimed in claim 1, characterized in that: 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 a set position, wherein the anti-wetting substance is titanium acetylacetonate or other substances with equivalent effects. The bearing parts coated with the coating are then placed in a constant temperature heating box, the temperature is controlled at 200-400°C and maintained for 15-60 minutes, so that the titanium acetylacetonate undergoes physical evaporation and chemical reaction, thereby generating a titanium oxide compound coating in situ in the set area.

5. A sealing structure of a liquid metal bearing as claimed in claim 4, characterized in that: The thickness 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 is 0.2-1.5 um.

6. A sealing structure of a liquid metal bearing as claimed in claim 1, characterized in that: A plurality of bolt mounting holes (10) extending vertically through the shaft sleeve (2), the end cover (3) and the bearing ring (4) are provided at positions where the fastening bolts (5) are connected. The plurality of fastening bolts (5) are arranged in a one-to-one correspondence 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). The plurality of exhaust holes (9) are in one-to-one correspondence with the plurality of bolt mounting holes (10).

7. A sealing structure of a liquid metal bearing as claimed in claim 1, characterized in that: A plurality of end cover bolt holes (13) are arranged on the upper end surface of the end cover (3), 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 arranged on the side surface of the end cover (3), and the plurality of end cover exhaust holes (14) are connected to the plurality of end cover bolt holes (13) in a one-to-one correspondence.

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

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