Liquid metal bearing dynamic balance correction system and method

Abstract

The present invention relates to a liquid metal bearing dynamic balance correction system and method applied to the field of CT tube technology. The dynamic balance correction system comprises an air circulation system, a liquid metal bearing system, and a test sensor system. The air circulation system comprises a sealed outer cover, an exhaust fan is arranged on the outer wall of the sealed outer cover, one end of the exhaust fan is connected to a gas circulation channel, and the end of the gas circulation channel away from the exhaust fan is connected to the inside of the sealed outer cover. The dynamic balance correction system of the present invention can effectively avoid the problem that the liquid metal in the bearing reacts with oxygen in the atmosphere, causing the viscosity of the liquid metal to change, and then causing the bearing performance to decrease when performing dynamic balance correction on the liquid metal bearing. The dynamic balance correction system can not only perform dynamic balance correction on the rotor, but also perform dynamic balance correction on the final product structure of the rotor and the stator, thereby greatly improving the accuracy and effect of the dynamic balance correction.

Description

Technical Field

[0001] The present invention relates to a dynamic balance correction system, and in particular to a liquid metal bearing dynamic balance correction system and method applied in the technical field of CT tubes. Background Art

[0002] The high-speed bearings used in CT tubes have high performance requirements due to their special usage scenarios, including high temperature, vacuum and other environments. Therefore, the bearing performance of CT tubes directly affects the performance of the entire tube. Currently, there are two main types of bearings for commercial tubes on the market: liquid metal bearings and ball bearings. Liquid metal bearings are the preferred accessories for high-heat capacity CT tubes due to their many advantages such as high speed, long life, and quietness. The basic principle of liquid metal bearings is that when the rotor rotates, the liquid metal between the rotor and the stator gathers into the gap between the stator and the rotor through the herringbone groove texture on the surface of the stator and finally forms a liquid with a certain film thickness, which greatly reduces the friction between the stator and the rotor.

[0003] The invention patent with publication number CN115472476B discloses a method and system for dynamic balancing correction of an anode assembly of an X-ray tube liquid metal bearing, wherein the method comprises: providing a process device for performing a dynamic balancing test on an anode assembly of an X-ray tube, wherein the anode assembly is an anode assembly that rotates based on a liquid metal bearing, and the process device comprises a mandrel and a rolling bearing sleeved on the mandrel; assembling the anode assembly to the process device so that the anode assembly can rotate relative to the mandrel under the support of the rolling bearing; fixing the mandrel and performing a dynamic balancing test on the anode assembly; and performing dynamic balancing correction on the anode assembly according to the result of the dynamic balancing test.

[0004] The invention patent with publication number CN118424703A discloses a liquid metal sliding bearing operation test bench for CT tubes. The invention can carry out various working condition tests, has strong operating stability, can control the temperature and vacuum environment separately, has controllable test variables, and is easy to operate. The driving motor stator and rotor cooperate to drive the test bearing to rotate, and there is no need to perform strict alignment operations on the test bearing.

[0005] In the prior art, the dynamic balance correction of liquid metal bearings is usually performed in an atmospheric environment. When the liquid metal bearings work in an atmospheric environment, the oxygen in the air easily reacts with the liquid metal, and the viscosity coefficient of the liquid changes, which eventually leads to a decrease in bearing performance. Therefore, the dynamic balance correction operation of liquid metal bearings in the prior art has strong limitations, which has a great impact on the actual bearing manufacturing and ball tube manufacturing. Therefore, we propose a liquid metal bearing dynamic balance correction system and method. Summary of the invention

[0006] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that when the liquid metal bearing works in an atmospheric environment, the oxygen in the air is easy to react with the liquid metal, and the viscosity coefficient of the liquid will change, which will eventually lead to a decrease in bearing performance.

[0007] In order to solve the above problems, the present invention provides a liquid metal bearing dynamic balance correction system, including an air circulation system, a liquid metal bearing system, and a test sensor system;

[0008] The air circulation system comprises a sealed outer cover, an exhaust fan is arranged on the outer wall of the sealed outer cover, one end of the exhaust fan is connected to a gas circulation channel, an end of the gas circulation channel away from the exhaust fan is connected to the inside of the sealed outer cover, and a fixed bracket is fixedly installed on the inner wall of the bottom end of the sealed outer cover;

[0009] The liquid metal bearing system includes a coil, a rotor, a stator, and a target plate. The coil is used to drive the rotor, and the stator is used to support the rotor. The rotor and the target plate are fixedly connected. A connecting hole matching the stator is opened on the fixed bracket, and the stator and the connecting hole are movably plugged.

[0010] The test sensor system includes eddy current sensor 1, eddy current sensor 2, rotation speed sensor, and vibration vector acceleration sensor.

[0011] In the above-mentioned liquid metal bearing dynamic balancing correction system, the reaction between the liquid metal in the liquid metal bearing and the oxygen in the atmosphere, which causes the viscosity of the liquid metal to change and thus causes the bearing performance to deteriorate, can be effectively avoided.

[0012] As a further improvement of the present application, a cover door movably and sealingly connected to the front of the sealed outer cover is provided, an air inlet pipe and an air outlet pipe are connected to the outer wall of the sealed outer cover, an air inlet valve is provided on the air inlet pipe, and an air outlet valve is provided on the air outlet pipe, and the air inlet valve and the air outlet valve are both located outside the sealed outer cover.

[0013] As a further improvement of the present application, eddy current sensor 1 and eddy current sensor 2 are respectively installed on the radial circumferential surface and axial plane of the target disk, and the distance between eddy current sensor 1 and eddy current sensor 2 and the target disk is 0.4-0.6mm. Eddy current sensor 1 and eddy current sensor 2 are used to test the displacement of the target disk.

[0014] As a further improvement of the present application, a rotation speed sensor is used to test the rotation speed and phase of the target disk through a laser reflection signal, and the rotation speed sensor can be installed at any position near the target disk. The vibration vector acceleration sensor is arranged at the connection between the stator and the fixed bracket to monitor the vibration value of the liquid metal bearing system.

[0015] As a further improvement of the present application, the air circulation system further includes a gas cooling device arranged on the gas circulation channel for reducing the gas temperature.

[0016] As another improvement of the present application, a method for correcting the dynamic balance of a liquid metal bearing comprises the following steps:

[0017] S1. Open the cover door and install the liquid metal bearing system into the sealed outer cover;

[0018] S2, installing the test sensor system into the sealed outer cover and closing the cover door;

[0019] S3, open the air inlet valve and the air outlet valve, fill the sealed outer cover with low-activity gas through the air inlet pipe, and exhaust the air in the sealed outer cover through the air outlet pipe until the sealed outer cover is filled with low-activity gas, then close the air inlet valve and the air outlet valve, and start the exhaust fan and the gas cooling device;

[0020] S4, start the coil, and test the rotation speed and corresponding displacement and vibration values ​​at this time through the test sensor system;

[0021] S5, open the cover door, add a test weight to the radial circumference of the target disk, and repeat steps S2 to S4;

[0022] S6. Calculate weight using vector diagram method and influence coefficient method;

[0023] S7, open the cover door, remove the test weight, and add a test weight of corresponding weight to the radial circumference of the target disk according to the calculated weight and the measured phase;

[0024] S8. Repeat steps S1 to S4 and steps S6 and S7 until the unbalanced value reaches the required value.

[0025] As yet another improved supplement of the present application, the low-activity gas includes nitrogen, argon, and helium.

[0026] To summarize, the dynamic balancing correction system in the present application can effectively avoid the reaction between the liquid metal in the liquid metal bearing and the oxygen in the atmosphere, which causes the viscosity of the liquid metal to change, and then leads to the problem of reduced bearing performance when performing dynamic balancing correction on the liquid metal bearing. It can not only perform dynamic balancing correction on the rotor, but also perform dynamic balancing correction on the final product structure of the rotor and stator, thereby greatly improving the accuracy and effect of the dynamic balancing correction. In addition, the air circulation system can also take away the heat released during the operation of the coil, so that the entire system can maintain long-term operation, close to the actual high-speed process, thereby further improving the accuracy and effect of the dynamic balancing correction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1This is a schematic diagram of the overall structure of the liquid metal bearing dynamic balancing correction system in this application;

[0028] Figure 2 It is a structural schematic diagram of the air circulation system in this application;

[0029] Figure 3 It is a schematic diagram of the structure of the liquid metal bearing system in this application;

[0030] Figure 4 is a system structure block diagram of the test sensor system in this application;

[0031] Figure 5 This is a flow chart of the method for dynamic balancing correction of liquid metal bearings in this application.

[0032] Description of the numbers in the figure:

[0033] 1. Sealed outer cover; 2. Exhaust fan; 3. Gas circulation channel; 4. Fixed bracket; 13. Inlet pipe; 14. Inlet valve; 15. Outlet pipe; 16. Outlet valve; 17. Gas cooling device; 5. Coil; 6. Rotor; 7. Stator; 8. Target plate; 9. Eddy current sensor 1; 10. Eddy current sensor 2; 11. Speed ​​sensor; 12. Vibration vector acceleration sensor. DETAILED DESCRIPTION

[0034] Two implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0035] The first implementation method:

[0036] Figure 1-Figure 4 A liquid metal bearing dynamic balance correction system is shown, comprising an air circulation system, a liquid metal bearing system, and a test sensor system;

[0037] The liquid metal bearing system includes a coil 5, a rotor 6, a stator 7, and a target plate 8. The coil 5 is used to drive the rotor 6, the stator 7 is used to support the rotor 6, the rotor 6 is fixedly connected to the target plate 8, the target plate 8 is a component that needs to be dynamically balanced, and the coil 5 is the main heat source;

[0038] The test sensor system includes an eddy current sensor 19, an eddy current sensor 210, a rotation speed sensor 11, and a vibration vector acceleration sensor 12. The eddy current sensor 19 and the eddy current sensor 210 are respectively installed on the radial circumferential surface and the axial plane of the target disk 8, and the distances between the eddy current sensor 19 and the eddy current sensor 210 and the target disk 8 are both 0.4-0.6 mm. The eddy current sensor 19 and the eddy current sensor 210 are used to test the displacement of the target disk 8. The rotation speed sensor 11 is used to test the rotation speed and phase of the target disk 8 through a laser reflection signal, and the rotation speed sensor 11 can be installed at any position near the target disk 8. The vibration vector acceleration sensor 12 is used to monitor the vibration value of the liquid metal bearing system. The unbalanced weight of different phases can be calculated through the relationship between the phase data and the vibration and displacement, and then the unbalanced amount can be reduced by increasing and decreasing the weight in a specific phase;

[0039] The air circulation system includes a sealed outer cover 1, a cover door movably and sealingly connected to the front of the sealed outer cover 1 is provided, an air inlet pipe 13 and an air outlet pipe 15 are connected on the outer wall of the sealed outer cover 1, an air inlet valve 14 is provided on the air inlet pipe 13, and an air outlet valve 16 is provided on the air outlet pipe 15, the air inlet valve 14 and the air outlet valve 16 are both located outside the sealed outer cover 1, the sealed outer cover 1 is used to close the entire test space to keep the internal atmosphere constant, and low-activity gases such as argon and nitrogen are filled into the sealed outer cover 1 during operation to ensure that the liquid metal in the liquid metal bearing system can maintain a stable state, a fixed bracket 4 is fixedly installed on the inner wall of the bottom end of the sealed outer cover 1, a connecting hole matching the stator 7 is opened on the fixed bracket 4, the stator 7 is movably plugged into the connecting hole, and a vibration vector acceleration sensor 12 is arranged at the connection between the stator 7 and the fixed bracket 4.

[0040] The dynamic balancing correction system in the present application can effectively avoid the reaction between the liquid metal in the liquid metal bearing and the oxygen in the atmosphere, which causes the viscosity of the liquid metal to change, and then leads to the problem of reduced bearing performance when performing dynamic balancing correction on the liquid metal bearing. It can not only perform dynamic balancing correction on the rotor, but also perform dynamic balancing correction on the final product structure of the rotor and stator, thereby greatly improving the accuracy and effect of dynamic balancing correction.

[0041] An exhaust fan 2 is arranged on the outer wall of the sealed outer cover 1, and one end of the exhaust fan 2 is connected to a gas circulation channel 3. The end of the gas circulation channel 3 away from the exhaust fan 2 is connected to the interior of the sealed outer cover 1. Starting the exhaust fan 2 can make the gas in the sealed outer cover 1 circulate continuously to reduce the working temperature of the coil 5. The air circulation system also includes a gas cooling device 17 arranged on the gas circulation channel 3. The gas cooling device 17 is used to reduce the gas temperature, thereby further reducing the working temperature of the coil 5. The gas cooling device 17 is a mature prior art, and its specific structure is not described here. Those skilled in the art can select a suitable type of cooling device as the gas cooling device 17 as appropriate. For example, the gas cooling device 17 can be a semiconductor refrigerator.

[0042] Under the action of the exhaust fan 2 and the gas circulation channel 3, the heat released by the coil 5 during operation can be taken away, so that the bearing can always operate at a high speed. The gas cooling device 17 can further take away the heat, so that the entire system can maintain long-term operation, close to the actual high-speed process, thereby further improving the accuracy and effect of dynamic balancing correction.

[0043] The second implementation method:

[0044] See also Figure 1-Figure 5 , a liquid metal bearing dynamic balance correction method, comprising the following steps:

[0045] S1. Open the cover door and install the liquid metal bearing system into the sealed outer cover 1;

[0046] S2, installing the test sensor system into the sealed outer cover 1 and closing the cover door;

[0047] S3, open the air inlet valve 14 and the air outlet valve 16, fill the sealed outer cover 1 with low-activity gas (such as nitrogen, argon, helium, etc.) through the air inlet pipe 13, and exhaust the air in the sealed outer cover 1 through the air outlet pipe 15 until the sealed outer cover 1 is filled with low-activity gas (the concentration of low-activity gas reaches more than 95%), then close the air inlet valve 14 and the air outlet valve 16, and start the exhaust fan 2 and the gas cooling device 17;

[0048] S4, start coil 5, and test the rotation speed and corresponding displacement and vibration value at this time through the test sensor system;

[0049] S5, open the cover door, add a test weight to the radial circumference of the target disc 8, and repeat steps S2 to S4;

[0050] S6. Calculate weight using vector diagram method and influence coefficient method;

[0051] S7, open the cover door, remove the test weight, and add a test weight of corresponding weight to the radial circumference position of the target plate 8 according to the calculated weight and the measured phase;

[0052] S8. Repeat steps S1 to S4 and steps S6 and S7 until the unbalanced value reaches the required value.

[0053] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A liquid metal bearing dynamic balance correction system, characterized in that: Including air circulation system, liquid metal bearing system, test sensor system; The air circulation system comprises a sealed outer cover (1), an exhaust fan (2) is arranged on the outer wall of the sealed outer cover (1), one end of the exhaust fan (2) is connected to a gas circulation channel (3), the end of the gas circulation channel (3) away from the exhaust fan (2) is connected to the interior of the sealed outer cover (1), and a fixing bracket (4) is fixedly mounted on the inner wall of the bottom end of the sealed outer cover (1); The liquid metal bearing system comprises a coil (5), a rotor (6), a stator (7), and a target plate (8); the coil (5) is used to drive the rotor (6); the stator (7) is used to support the rotor (6); the rotor (6) and the target plate (8) are fixedly connected; a connection hole matching the stator (7) is provided on the fixed bracket (4); and the stator (7) is movably plugged into the connection hole; The test sensor system comprises an eddy current sensor 1 (9), an eddy current sensor 2 (10), a rotation speed sensor (11), and a vibration vector acceleration sensor (12).

2. A liquid metal bearing dynamic balance correction system according to claim 1, characterized in that: The front of the sealed outer cover (1) is provided with a cover door which is movably and hermetically connected thereto; an air inlet pipe (13) and an air outlet pipe (15) are connected to the outer wall of the sealed outer cover (1); an air inlet valve (14) is provided on the air inlet pipe (13); an air outlet valve (16) is provided on the air outlet pipe (15); and the air inlet valve (14) and the air outlet valve (16) are both located outside the sealed outer cover (1).

3. A liquid metal bearing dynamic balance correction system according to claim 1, characterized in that: The eddy current sensor 1 (9) and the eddy current sensor 2 (10) are respectively installed on the radial circumferential surface and the axial plane of the target disk (8), and the distances between the eddy current sensor 1 (9) and the eddy current sensor 2 (10) and the target disk (8) are both 0.4-0.6 mm. The eddy current sensor 1 (9) and the eddy current sensor 2 (10) are used to test the displacement of the target disk (8).

4. A liquid metal bearing dynamic balance correction system according to claim 1, characterized in that: The rotation speed sensor (11) is used to test the rotation speed and phase of the target disk (8) through a laser reflection signal, and the vibration vector acceleration sensor (12) is arranged at the connection between the stator (7) and the fixed bracket (4) and is used to monitor the vibration value of the liquid metal bearing system.

5. The liquid metal bearing dynamic balance correction system according to claim 1, characterized in that: The air circulation system further comprises a gas cooling device (17) arranged on the gas circulation passage (3) for reducing the gas temperature.

6. A liquid metal bearing dynamic balance correction method, applied to the liquid metal bearing dynamic balance correction system according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Open the cover door and install the liquid metal bearing system into the sealed outer cover (1); S2, installing the test sensor system into the sealed housing (1) and closing the housing door; S3, opening the air inlet valve (14) and the air outlet valve (16), filling the sealed outer cover (1) with low-activity gas through the air inlet pipe (13), and exhausting the air in the sealed outer cover (1) through the air outlet pipe (15) until the sealed outer cover (1) is filled with low-activity gas, then closing the air inlet valve (14) and the air outlet valve (16), and starting the exhaust fan (2) and the gas cooling device (17); S4, start the coil (5), and test the rotation speed and the corresponding displacement and vibration values ​​at this time through the test sensor system; S5, opening the cover door, adding a test weight to the radial circumference of the target disk (8), and repeating steps S2 to S4; S6. Calculate weight using vector diagram method and influence coefficient method; S7, open the cover door, remove the test weight, and add a test weight of corresponding weight to the radial circumference position of the target plate (8) according to the calculated weight and the measured phase; S8. Repeat steps S1 to S4 and steps S6 and S7 until the unbalanced value reaches the required value.

7. A method for correcting the dynamic balance of a liquid metal bearing according to claim 6, characterized in that: The low-activity gas includes nitrogen, argon and helium.

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