For flexible rotors, high-speed dynamic balancing is generally required to ensure a good balance state. This article provides a specific explanation of the high-speed dynamic balancing machine created by Zhonghua Science and Technology Intelligence. The dynamic characteristics of the swing frame of a high-speed dynamic balancing machine directly affect the accuracy of the dynamic balancing test. In order to improve the dynamic characteristics of the swing frame of the dynamic balancing machine, the influence of the dynamic main stiffness rod on the dynamic stiffness of the swing frame of the balancing machine was analyzed.
Firstly, use the finite element analysis software ANSYS to establish a model of the high-speed dynamic balancing machine swing frame, conduct modal analysis on it, and obtain the frequencies and vibration modes of each order of the dynamic balancing machine swing frame, excluding any fixed vibration modes that have no impact on the operation of the dynamic balancing machine swing frame. Conduct modal analysis on different structures of the swing frame, compare and calculate the structures, and remove the structures that do not affect the natural frequency of the swing frame of the dynamic balancing machine. Secondly, on the basis of simplifying the model, five improvement methods for the main stiffness rod of the pendulum frame are proposed. Perform harmonic response analysis on various improved swing frames to obtain the relationship curve between dynamic stiffness and frequency. The results show that changing the structural size or material characteristics of the main stiffness rod appropriately will change the dynamic stiffness of the swing frame. Therefore, in the design process, the structural dimensions and material characteristics of the main stiffness rod can be appropriately changed to meet the design requirements of the dynamic balancing machine swing frame.
Below is an analysis of several targeted issues with high-speed dynamic balancing machines:
The cost of dismantling and installing a gas turbine and its control system during testing is relatively high. If there is no special demand or sufficient cost support, it is not suitable to choose this type of solution. It only considers the possible imbalance effect caused by processing and disassembly, and ignores the influence of low temperature phenomenon and Jet stream and other components on vibration under actual working conditions.
1. High speed drive issue: Initially, a high-speed dynamic balancing machine was designed for testing the rotor to study the rotor dynamics under high-speed rotation and the technologies that affect the high-speed dynamic balancing machine. Due to the significant gap between China and developed Western countries in precision and high-precision machining scale, and the fact that foreign countries maintain technical confidentiality in high-precision machine tool equipment and instruments, it is difficult for China to meet the needs of ultra-high precision in the processing and disassembly of micro turbine engines. Due to insufficient quality of rotor materials and errors in the machining and disassembly of blades and impellers, instability and the possibility of significant imbalance in the rotor may occur.
2. Rotor detection problem: In order to simplify the testing process, the design of the induction rotor is an idealized technology with excellent dynamic balance characteristics. The rotor operates idealized under complex and difficult working conditions. In summary, it is necessary to perform process dynamic balancing on the centimeter level rotor to ensure that it not only has excellent vibration characteristics at working speed, but also works stably during the process of speed increase or decrease. Choosing an electrical drive for testing not only reduces the cost of testing, but also makes it easy to master and protect the motor drive. However, it is rare to have a motor that can reach 120000 revolutions per minute and has sufficient power, and there are no truly good cases and experience. The driving of high-speed dynamic balancing machines relies heavily on thermal power.
3. Balance machine bearing problem: This type of micro high-speed rotor has a working speed that is far above its second speed, which belongs to flexible rotors. If the dynamic imbalance is too large, it is difficult for the rotor to reach this speed during the acceleration process and cannot work normally. Whether the balance machine bearings on the market can truly meet this need still requires further testing and demonstration.
The soft support high-speed spindle dynamic balancing machine adopts universal coupling transmission, which can achieve various balancing speeds with high accuracy, convenient operation, and high work efficiency. High speed dynamic balancing machine is suitable for vacuum pumps, centrifugal pump rotors, motor rotors, crushing blade shafts, rollers, steam turbine rotors, etc.
A high-speed dynamic balancing machine is an instrument used to measure the imbalance of a rotor, which is calibrated based on the measured results. High speed dynamic balancing machines are widely used in various fields and can be involved in various industries; It can perform dynamic balance measurements on single, double, and multiple calibration faces. The equipment has the characteristics of high efficiency, accurate accuracy, intuitive display, reliable quality, and convenient maintenance.
Firstly, we need to mention that the main structure of its engine is a micro high-speed rotor dynamic balance system, and its characteristics will directly affect the overall performance. Under current technological conditions, vibration signal detection can be achieved. High speed dynamic balancing machines can achieve centimeter level rotors, but there is currently no high-speed dynamic balancing machine in China with a balancing speed of up to 120000 revolutions per minute, and there is no relatively mature micro and high-speed dynamic balancing technology.
Although in such simplified designs, it is difficult to meet the basic conditions such as high-speed drive, frequency converter, support bearings, sliding equipment, vibration sensors, and signal processors required for balancing the rotor dynamic balance test bench with a working speed of 120000 rpm.
The dynamic imbalance caused by the imbalance at operating speeds of over 100000 revolutions per minute can seriously affect the vibration, stability, and other performance of the engine. The rotor deflection and internal stress caused by dynamic imbalance can accelerate the aging of bearings, shaft seals, and other parts, reduce work efficiency, and even cause various types of work to fail to operate normally. Considering the ability to work for a long time, lifespan, cost, and the presence of original unbalanced rotors, the mechanical bearing support is the best solution.
Firstly, use the finite element analysis software ANSYS to establish a model of the high-speed dynamic balancing machine swing frame, conduct modal analysis on it, and obtain the frequencies and vibration modes of each order of the dynamic balancing machine swing frame, excluding any fixed vibration modes that have no impact on the operation of the dynamic balancing machine swing frame. Conduct modal analysis on different structures of the swing frame, compare and calculate the structures, and remove the structures that do not affect the natural frequency of the swing frame of the dynamic balancing machine. Secondly, on the basis of simplifying the model, five improvement methods for the main stiffness rod of the pendulum frame are proposed. Perform harmonic response analysis on various improved swing frames to obtain the relationship curve between dynamic stiffness and frequency. The results show that changing the structural size or material characteristics of the main stiffness rod appropriately will change the dynamic stiffness of the swing frame. Therefore, in the design process, the structural dimensions and material characteristics of the main stiffness rod can be appropriately changed to meet the design requirements of the dynamic balancing machine swing frame.
Below is an analysis of several targeted issues with high-speed dynamic balancing machines:
The cost of dismantling and installing a gas turbine and its control system during testing is relatively high. If there is no special demand or sufficient cost support, it is not suitable to choose this type of solution. It only considers the possible imbalance effect caused by processing and disassembly, and ignores the influence of low temperature phenomenon and Jet stream and other components on vibration under actual working conditions.
1. High speed drive issue: Initially, a high-speed dynamic balancing machine was designed for testing the rotor to study the rotor dynamics under high-speed rotation and the technologies that affect the high-speed dynamic balancing machine. Due to the significant gap between China and developed Western countries in precision and high-precision machining scale, and the fact that foreign countries maintain technical confidentiality in high-precision machine tool equipment and instruments, it is difficult for China to meet the needs of ultra-high precision in the processing and disassembly of micro turbine engines. Due to insufficient quality of rotor materials and errors in the machining and disassembly of blades and impellers, instability and the possibility of significant imbalance in the rotor may occur.
2. Rotor detection problem: In order to simplify the testing process, the design of the induction rotor is an idealized technology with excellent dynamic balance characteristics. The rotor operates idealized under complex and difficult working conditions. In summary, it is necessary to perform process dynamic balancing on the centimeter level rotor to ensure that it not only has excellent vibration characteristics at working speed, but also works stably during the process of speed increase or decrease. Choosing an electrical drive for testing not only reduces the cost of testing, but also makes it easy to master and protect the motor drive. However, it is rare to have a motor that can reach 120000 revolutions per minute and has sufficient power, and there are no truly good cases and experience. The driving of high-speed dynamic balancing machines relies heavily on thermal power.
3. Balance machine bearing problem: This type of micro high-speed rotor has a working speed that is far above its second speed, which belongs to flexible rotors. If the dynamic imbalance is too large, it is difficult for the rotor to reach this speed during the acceleration process and cannot work normally. Whether the balance machine bearings on the market can truly meet this need still requires further testing and demonstration.
The soft support high-speed spindle dynamic balancing machine adopts universal coupling transmission, which can achieve various balancing speeds with high accuracy, convenient operation, and high work efficiency. High speed dynamic balancing machine is suitable for vacuum pumps, centrifugal pump rotors, motor rotors, crushing blade shafts, rollers, steam turbine rotors, etc.
A high-speed dynamic balancing machine is an instrument used to measure the imbalance of a rotor, which is calibrated based on the measured results. High speed dynamic balancing machines are widely used in various fields and can be involved in various industries; It can perform dynamic balance measurements on single, double, and multiple calibration faces. The equipment has the characteristics of high efficiency, accurate accuracy, intuitive display, reliable quality, and convenient maintenance.
Firstly, we need to mention that the main structure of its engine is a micro high-speed rotor dynamic balance system, and its characteristics will directly affect the overall performance. Under current technological conditions, vibration signal detection can be achieved. High speed dynamic balancing machines can achieve centimeter level rotors, but there is currently no high-speed dynamic balancing machine in China with a balancing speed of up to 120000 revolutions per minute, and there is no relatively mature micro and high-speed dynamic balancing technology.
Although in such simplified designs, it is difficult to meet the basic conditions such as high-speed drive, frequency converter, support bearings, sliding equipment, vibration sensors, and signal processors required for balancing the rotor dynamic balance test bench with a working speed of 120000 rpm.
The dynamic imbalance caused by the imbalance at operating speeds of over 100000 revolutions per minute can seriously affect the vibration, stability, and other performance of the engine. The rotor deflection and internal stress caused by dynamic imbalance can accelerate the aging of bearings, shaft seals, and other parts, reduce work efficiency, and even cause various types of work to fail to operate normally. Considering the ability to work for a long time, lifespan, cost, and the presence of original unbalanced rotors, the mechanical bearing support is the best solution.
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