Dynamic balance correction device of liquid metal bearing

Abstract

The utility model provides a dynamic balance correction device of a liquid metal bearing, which comprises a dynamic balance host and a vacuum chamber, a test support and a speed measurement sensor are arranged in the vacuum chamber, a tool and a stator coil are arranged on the test support, one end of the tool far away from the test support is connected with an X-ray tube anode assembly, and the dynamic balance host is connected with the speed measurement sensor. The outer side wall of the vacuum chamber is sequentially connected with a molecular pump and a backing pump through a pipeline I; the outer side wall of the vacuum chamber is connected with an inert gas tank through a second pipeline. Compared with a traditional dynamic balance scheme, the dynamic balance correcting device of the liquid metal bearing and a correcting method of the dynamic balance correcting device of the liquid metal bearing have the advantages that oxygen in the operation environment of the anode assembly is exhausted, the contact time of liquid metal and the oxygen is shortened, generation of oxide is reduced, failure of a liquid metal sealing face is avoided, and product quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of X-ray tubes, in particular to a dynamic balance correction device for a liquid metal bearing. Background Art

[0002] The anode bearing of the X-ray tube is its core component. While operating at a high speed of about 400°C, it must also withstand the radial load generated by the target disk and the centrifugal force of more than 30G generated by the rotation of the tube. The traditional ball bearing structure is not stable enough when running at high speed. It is prone to low speed or jamming after long-term operation. At this time, exposure will cause local heat concentration on the anode rhenium tungsten target surface, resulting in metal evaporation, causing sparks and causing failure of the X-ray tube.

[0003] Liquid metal bearings use gallium, indium, and tin alloys as lubricating and supporting media between friction pairs, increasing the contact area and overcoming the shortcomings of ball bearings. While having an extremely low friction coefficient, high load-bearing capacity, and high thermal conductivity, they can achieve low noise, high speed, and long-term operation. They are widely used in high-end CT and DSA tubes.

[0004] Figure 1 In the invention, the X-ray liquid metal bearing is mainly composed of gallium indium tin liquid metal 100, a main shaft 101, a sleeve 102 and a limit ring 104; the liquid metal 100 is stored between the shaft 101 and the sleeve 102, and an adhesion connection is formed on the wetted surfaces of the main shaft 101 and the sleeve 102, and a high-pressure seal is generated at the end face 103 due to the high surface tension in a vacuum environment to keep the liquid metal inside the bearing; however, in the assembly of the liquid metal bearing, because the gallium in the liquid metal is easily oxidized in the air to form gallium oxide, its surface tension is destroyed at the end face 103, and the liquid metal is easily leaked, causing the liquid metal bearing to fail.

[0005] Figure 2 In the invention, the liquid metal bearing 201, the target plate 200 and the magnetic sleeve 202 form an anode assembly 302, and the rotation speed during operation is as high as 9000r / min or more. In order to eliminate the poor dynamic balancing accuracy caused by dimensional deviation, assembly error and material unevenness generated during machining, dynamic balancing correction must be performed to readjust the mass distribution of the anode assembly so that its axis coincides with the central principal inertia axis. In order to make the dynamic balancing accuracy of the anode assembly meet the performance requirements, the dynamic balancing correction must be repeated many times. Therefore, in order to reduce the exposure time in the air during dynamic balancing correction, it is expected to develop a dynamic balancing correction device and method for liquid metal bearings. Summary of the invention

[0006] The utility model aims to overcome and supplement the deficiencies in the prior art, and to provide a dynamic balance correction device for a liquid metal bearing, which can significantly reduce oxidized liquid metal to achieve the purpose of reliably sealing the liquid metal.

[0007] The technical solution adopted by the utility model is:

[0008] A dynamic balancing correction device for a liquid metal bearing, comprising a dynamic balancing mainframe and a vacuum chamber, wherein a test bracket and a speed sensor are arranged in the vacuum chamber, a tooling and a stator coil are arranged on the test bracket, an end of the tooling away from the test bracket is connected to an X-ray tube anode assembly, the dynamic balancing mainframe is connected to the speed sensor, the outer wall of the vacuum chamber is connected to a molecular pump and a front pump in sequence through a pipe 1; the outer wall of the vacuum chamber is connected to an inert gas tank through a pipe 2, and the stator coil is connected to a frequency converter.

[0009] Preferably, in the dynamic balance correction device for the liquid metal bearing, an isolation valve 1 is provided on a pipe 1 between the outer wall of the vacuum chamber and the molecular pump, and an isolation valve 2 is provided on a pipe 1 between the molecular pump and the front-stage pump.

[0010] Preferably, in the dynamic balance correction device for the liquid metal bearing, an air charging valve is provided on the second pipeline.

[0011] Advantages of the utility model:

[0012] (1) Compared with the traditional dynamic balancing scheme, the dynamic balancing correction device of the liquid metal bearing of the utility model discharges the oxygen in the operating environment of the anode assembly, reduces the contact time between the liquid metal and oxygen, reduces the generation of oxides, avoids the failure of the liquid metal sealing surface, and improves the quality of the product.

[0013] (2) The dynamic balancing correction device for liquid metal bearings of the utility model enables the dynamic balancing test to be performed in a vacuum environment, thereby reducing the running resistance, enabling the anode main component to run at a higher speed, reducing the impact of the environment on the test, and improving the test accuracy of the dynamic balancing machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the main structure of the liquid metal bearing of the X-ray tube.

[0015] Figure 2 This is a schematic diagram of the main structure of the liquid metal anode assembly of the X-ray tube.

[0016] Figure 3 It is a schematic structural diagram of the dynamic balance correction device of the liquid metal bearing of the present utility model.

[0017] Figure 4 This is a process flow chart of Example 2 to Example 4. DETAILED DESCRIPTION

[0018] The utility model is further described below in conjunction with specific embodiments.

[0019] Example 1

[0020] like Figure 3 A dynamic balancing correction device for a liquid metal bearing, comprising: a dynamic balancing host 300 and a vacuum chamber 306, wherein a test bracket 305 and a speed sensor 301 are arranged in the vacuum chamber 306, a tool 304 and a stator coil 303 are arranged on the test bracket 305, an end of the tool 304 away from the test bracket 305 is connected to an X-ray tube anode assembly 302, the dynamic balancing host 300 is connected to the speed sensor 301, and the outer wall of the vacuum chamber 306 is connected to a molecular pump 309 and a pre-stage pump 311 in sequence through a pipeline 1; the outer wall of the vacuum chamber 306 is connected to an inert gas tank through a pipeline 2, and the stator coil 303 is connected to a frequency converter 312.

[0021] An isolation valve 1 308 is provided on the first pipe between the outer wall of the vacuum chamber 306 and the molecular pump 309 , an isolation valve 2 310 is provided on the first pipe between the molecular pump 309 and the front pump 311 ; and an inflation valve 307 is provided on the second pipe.

[0022] Example 2

[0023] like Figure 3-4 , a correction method for a dynamic balance correction device of a liquid metal bearing, wherein: comprising the following steps:

[0024] S1. Connect the liquid metal anode assembly 302 to the tooling 304 and fix it to the test stand 305;

[0025] S2. Open the isolation valve 1 308, isolation valve 2 310, front pump 311 and molecular pump 309 respectively to evacuate the vacuum chamber 306 to a set value of 5.0×10 -1 mbar;

[0026] S3. The X-ray tube anode assembly 302 includes a liquid metal bearing 201, a target plate 200 and a magnetic sleeve 202. The frequency converter 312 drives the X-ray tube anode assembly 302 to rotate through the stator coil 303. Specifically, the frequency converter 312 outputs three-phase alternating current to the stator coil 303 to generate a rotating magnetic field. The magnetic field drives the magnetic sleeve 202 on the bearing assembly 302 to rotate the anode assembly 302. The frequency converter 312 outputs three-phase alternating current to the stator to generate a rotating magnetic field. The magnetic field drives the magnetic sleeve 202 on the X-ray tube anode assembly 302 to rotate the X-ray tube anode assembly 302. The rotation speed of the X-ray tube anode assembly 302 is 1000rmp / min. Then, the X-ray tube anode assembly 302 is subjected to a dynamic balance test.

[0027] S4. Close the isolation valve 308, the isolation valve 2 310, the front pump 311, and the molecular pump 309, open the charging valve 307 to charge the vacuum chamber 306 with inert gas, which is nitrogen. The vacuum degree of the vacuum chamber 306 reaches 5.0×10 -1 mbar;

[0028] S5. According to the test results, the X-ray tube anode assembly 302 is dynamically balanced; if the correction does not achieve dynamic balance, repeat steps S2-S4 until dynamic balance is achieved;

[0029] S6. Calibration is completed and a test report is generated.

[0030] Example 3

[0031] like Figure 3-4 , a correction method for a dynamic balance correction device of a liquid metal bearing, wherein: comprising the following steps:

[0032] S1. Connect the liquid metal anode assembly 302 to the tooling 304 and fix it to the test stand 305;

[0033] S2. Open the isolation valve 1 308, isolation valve 2 310, front pump 311 and molecular pump 309 respectively to evacuate the vacuum chamber 306 to a set value of 5.0×10 -2 mbar;

[0034] S3. The X-ray tube anode assembly 302 includes a liquid metal bearing 201, a target plate 200 and a magnetic sleeve 202. The frequency converter 312 drives the X-ray tube anode assembly 302 to rotate through the stator coil 303. Specifically, the frequency converter 312 outputs three-phase alternating current to the stator coil 303 to generate a rotating magnetic field. The magnetic field drives the magnetic sleeve 202 on the bearing assembly 302 to rotate the anode assembly 302. The frequency converter 312 outputs three-phase alternating current to the stator to generate a rotating magnetic field. The magnetic field drives the magnetic sleeve 202 on the X-ray tube anode assembly 302 to rotate the X-ray tube anode assembly 302. The rotation speed of the X-ray tube anode assembly 302 is 2000rmp / min. Then, the X-ray tube anode assembly 302 is subjected to a dynamic balance test.

[0035] S4. Close the isolation valve 308, the isolation valve 2 310, the front pump 311, and the molecular pump 309, open the charging valve 307 to charge the vacuum chamber 306 with an inert gas, which is argon. The vacuum degree of the vacuum chamber 306 reaches 5.0×10 -2 mbar;

[0036] S5. According to the test results, the X-ray tube anode assembly 302 is dynamically balanced; if the correction does not achieve dynamic balance, repeat steps S2-S4 until dynamic balance is achieved;

[0037] S6. Calibration is completed and a test report is generated.

[0038] Example 4

[0039] like Figure 3-4 , a correction method for a dynamic balance correction device of a liquid metal bearing, wherein: comprising the following steps:

[0040] S1. Connect the liquid metal anode assembly 302 to the tooling 304 and fix it to the test stand 305;

[0041] S2. Open the isolation valve 1 308, isolation valve 2 310, front pump 311 and molecular pump 309 respectively to evacuate the vacuum chamber 306 to a set value of 5.0×10 -3 mbar;

[0042] S3. The X-ray tube anode assembly 302 includes a liquid metal bearing 201, a target plate 200 and a magnetic sleeve 202. The frequency converter 312 drives the X-ray tube anode assembly 302 to rotate through the stator coil 303. Specifically, the frequency converter 312 outputs three-phase alternating current to the stator coil 303 to generate a rotating magnetic field. The magnetic field drives the magnetic sleeve 202 on the bearing assembly 302 to rotate the anode assembly 302. The frequency converter 312 outputs three-phase alternating current to the stator to generate a rotating magnetic field. The magnetic field drives the magnetic sleeve 202 on the X-ray tube anode assembly 302 to rotate the X-ray tube anode assembly 302. The rotation speed of the X-ray tube anode assembly 302 is 3000rmp / min. Then, the X-ray tube anode assembly 302 is subjected to a dynamic balancing test.

[0043] S4. Close the isolation valve 308, the isolation valve 2 310, the front pump 311, and the molecular pump 309, open the charging valve 307 to charge the vacuum chamber 306 with inert gas, which is one or both of nitrogen and argon. The vacuum degree of the vacuum chamber 306 reaches 5.0×10 -3 mbar;

[0044] S5. According to the test results, the X-ray tube anode assembly 302 is dynamically balanced; if the correction does not achieve dynamic balance, repeat steps S2-S4 until dynamic balance is achieved;

[0045] S6. Calibration is completed and a test report is generated.

[0046] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to examples, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A dynamic balance correction device for a liquid metal bearing, characterized in that: The invention comprises a dynamic balancing mainframe (300) and a vacuum chamber (306), wherein a test bracket (305) and a speed sensor (301) are arranged in the vacuum chamber (306), a tool (304) and a stator coil (303) are arranged on the test bracket (305), an end of the tool (304) away from the test bracket (305) is connected to an X-ray tube anode assembly (302), the dynamic balancing mainframe (300) is connected to the speed sensor (301), and an outer wall of the vacuum chamber (306) is connected to a molecular pump (309) and a front pump (311) in sequence through a first pipeline; the outer wall of the vacuum chamber (306) is connected to an inert gas tank through a second pipeline, and the stator coil (303) is connected to a frequency converter (312).

2. The dynamic balance correction device for a liquid metal bearing according to claim 1, characterized in that: An isolation valve 1 (308) is provided on the first pipe between the outer wall of the vacuum chamber (306) and the molecular pump (309), and an isolation valve 2 (310) is provided on the first pipe between the molecular pump (309) and the fore-stage pump (311).

3. The dynamic balance correction device for a liquid metal bearing according to claim 1, characterized in that: An air charging valve (307) is provided on the second pipeline.

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