High-reliability marine stator and rotor assembling method

Abstract

The invention discloses a high-reliability marine stator and rotor assembly method, relates to the technical field of marine motor assembly, and aims to solve the problem of dynamic air gap drift of a motor in an offshore power engine room in a salt mist damp heat and load fluctuation environment. A graphite enhanced elastic compensation ring is designed, a buffer allowance is reserved, a six-degree-of-freedom laser alignment system is adopted to preset micro-eccentricity, and a micro-sliding flexible key and a piezoelectric displacement piece are mounted at a key groove part, so that real-time monitoring and dynamic adjustment are realized. After the first flight, a monitoring threshold value is corrected through data analysis and solidified as a service reference, and it is ensured that the air gap stability and the fault pre-judgment capacity are synchronously improved; the method effectively suppresses thermal-mechanical coupling drift, improves the economy of the whole life cycle of a ship, is suitable for motor assembly in a severe marine environment, reduces the manual adjustment frequency, and provides important support for the reliability and efficiency of a ship power system.

Description

Technical Field

[0001] The invention relates to the technical field of marine motor assembly, in particular to a high-reliability marine stator and rotor assembly method. Background Art

[0002] Offshore engine rooms are exposed to an extreme environment year-round, characterized by salt spray, humidity, heat, and fluctuating loads. After assembly, motors are subjected to continuous thermal cycling and hull bending and twisting. The oriented silicon steel used in the stator and the permanent magnet material in the rotor expand at different rates when heated. If this difference isn't adequately accounted for during assembly, the uniform air gap between the rotor and stator will subtly contract and expand with temperature fluctuations, creating a dynamic drift similar to slow breathing.

[0003] After searching, a patent application with application publication number CN111106729A discloses a method for assembling the stator and rotor of a motor to the shaft. The method is based on a motor composed of a stator assembly, a rotor assembly, an end cover and a bearing assembly. Feature stoppers for detection are pre-processed at both ends of the stator base of the stator assembly. The feature stoppers are processed based on the actual stator iron core (axis), and their coaxiality is determined according to the design. The shaft extensions at both ends of the rotor assembly and the bearing stop have coaxiality requirements. The end cover is provided with bearing up, down, left and right fine-tuning assemblies. The feature stoppers at both ends of the base are used as references. A high-precision three-coordinate measuring tool is used to detect the coaxiality between the feature stoppers and the corresponding rotor shaft extension sections. The end cover bearing fine-tuning assembly and external tooling are used to adjust the position of the rotor assembly in the X, Y and Z directions respectively, so as to achieve the purpose of improving the installation coaxiality between the stator and the rotor.

[0004] In light of the above background:

[0005] Due to inadequate thermal expansion and contraction compensation, the air gap undergoes periodic fluctuations during service. This fluctuation first disrupts the symmetry of the magnetic field distribution, further increasing leakage flux and localized eddy current heating. This then amplifies high-frequency sound pressure, creating a piercing whine and accelerating permanent magnet demagnetization and winding aging. If left unchecked, assembly accuracy and thermal stability could be compromised, potentially triggering an emergency shutdown or even forcing the ship to reduce speed. Therefore, high-reliability marine stator and rotor assembly methods must incorporate thermal compensation structures and subsequent monitoring measures into the assembly process to prevent dynamic air gap drift from cascading failures.

[0006] To this end, the present invention provides a high-reliability marine stator and rotor assembly method. Summary of the Invention

[0007] (1) Technical problems solved

[0008] To address the shortcomings of existing technologies, the present invention provides a highly reliable marine stator and rotor assembly method. This method establishes a temperature-gap envelope curve before assembly, designs a graphite-reinforced elastic compensation ring with a buffer reserve, uses a six-degree-of-freedom laser alignment system to preset micro-eccentricity, and installs micro-sliding flexible keys and piezoelectric displacement plates in the keyway, enabling real-time monitoring and dynamic adjustment. Monitoring thresholds are corrected through data analysis and solidified as service benchmarks, ensuring simultaneous improvements in air gap stability and fault prediction capabilities. This method effectively suppresses thermal-mechanical coupling drift, improving the economic efficiency of the vessel's entire lifecycle. The method is suitable for motor assembly in harsh marine environments and reduces the frequency of manual adjustments, thereby resolving the technical issues discussed in the background art.

[0009] (2) Technical solution

[0010] In order to achieve the above objectives, the present invention is implemented through the following technical solutions

[0011] A high-reliability marine stator and rotor assembly method includes, before assembly, generating a temperature-clearance envelope curve by integrating finite element simulation and sample testing, and writing the curve into a database as a baseline for thermal compensation design;

[0012] According to the temperature-clearance envelope curve, a graphite-reinforced elastic compensation ring is press-fitted on the outer circle of the rotor and a controllable buffer margin is reserved;

[0013] Using a six-degree-of-freedom laser alignment system, the micro-eccentricity of the stator and rotor axis is preset according to the temperature-clearance envelope curve, and the relevant data is written into the assembly control table;

[0014] A micro-sliding flexible key is installed in the keyway and a piezoelectric displacement plate is embedded to collect displacement and temperature data. The gap variation characteristic and thermal hysteresis slip characteristic are extracted through two-stage processing. These are then input into a radial basis function model in parallel to generate dynamic stability coefficients, which drive the monitoring unit to issue adjustment commands.

[0015] By comparing the historical curves of keyway slip and dynamic stability coefficient, the monitoring threshold is corrected and solidified as the air gap status benchmark during the service phase.

[0016] Furthermore, the thermal expansion of the stator and rotor components is modeled through simulation analysis, and physical tests are performed on samples of the stator and rotor components to measure the actual thermal expansion; the simulation analysis data is combined with the physical test data to obtain an accurate data set representing the temperature-air gap relationship;

[0017] A polynomial curve is fitted to the precise data set to generate a temperature-air gap envelope curve, and the temperature-air gap envelope curve is stored in a database.

[0018] Furthermore, a graphite-reinforced elastic material is selected to make the compensation ring. According to the analysis results of the temperature-gap envelope curve, the thickness, width and cross-sectional thickness of the compensation ring are designed so that the elastic deformation of the compensation ring is not less than the maximum change of the air gap.

[0019] Furthermore, the compensation ring is mounted on the outer surface of the rotor by a press-fitting process, and the radial force applied is precisely controlled to form a preload force;

[0020] A buffer margin is reserved to cope with expansion or contraction caused by temperature changes. The buffer margin is determined by multiplying the maximum change in the air gap by a safety factor of 1.2 to 1.5. The initial deformation of the compensation ring is controlled by adjusting the radial force.

[0021] Furthermore, a temperature-gap envelope curve is extracted from the assembly database, wherein the temperature-gap envelope curve describes a continuous variation relationship of the air gap with temperature;

[0022] Determine the operating temperature range of the motor and calculate the maximum change in the air gap within the operating temperature range; calculate the average value of the air gap within the operating temperature range as a benchmark for micro-eccentricity design.

[0023] Furthermore, the micro-eccentricity is determined by an optimization method so as to minimize the deviation between the actual air gap and the ideal air gap within the operating temperature range;

[0024] A six-degree-of-freedom laser alignment system is deployed to measure and adjust the position parameters of the stator and rotor in real time to ensure that the offset between the stator and rotor axis reaches the optimal micro-eccentricity; the adjusted position data, which includes the micro-eccentricity and axis coordinates, is recorded, and an assembly control table is generated and stored in the assembly database.

[0025] Furthermore, a micro-sliding flexible key made of high-strength alloy steel and coated with a wear-resistant coating is installed in the keyway of the motor. A piezoelectric displacement plate made of piezoelectric ceramic material is embedded inside to collect displacement and temperature signals in real time at a frequency of 100 times per second.

[0026] The displacement signal is subjected to Fourier transform to extract the low-frequency component in the frequency range of 0 to 10 Hz, which is defined as the gap change characteristic.

[0027] Furthermore, the temperature signal and displacement signal are analyzed in the time domain, and the thermal hysteresis slip characteristic is calculated as the ratio of the temperature change rate to the displacement change rate. The gap change characteristic and the thermal hysteresis slip characteristic are input into a pre-trained radial basis function neural network model to output the dynamic stability coefficient.

[0028] The monitoring unit compares the dynamic stability control coefficient with the preset threshold, generates an adjustment instruction and transmits it to the control center through the wireless communication module.

[0029] Furthermore, the piezoelectric displacement plate is used to continuously monitor the slip of the micro-sliding flexible key at a frequency of once per minute, and the dynamic stability coefficient generated by the radial basis function model is recorded at the same time;

[0030] By performing a time series analysis on the slip and dynamic stability coefficient collected during the maiden voyage, a historical curve is generated to determine the maximum slip and the maximum deviation of the dynamic stability coefficient, and to correct the monitoring threshold.

[0031] Furthermore, the method for correcting the monitoring threshold is as follows: multiply the maximum deviation of the dynamic stability control coefficient by the adjustment coefficient 1.5 and the maximum value of the slip amount by the adjustment coefficient 0.01, and then add them to the initial monitoring threshold;

[0032] The corrected monitoring threshold is solidified as the air gap status reference value during the service phase, and during the service phase, the monitoring unit compares the dynamic stability control coefficient with the solidified monitoring threshold in real time to determine whether the air gap status is abnormal.

[0033] (3) Beneficial effects

[0034] The present invention provides a high-reliability marine stator and rotor assembly method, which has the following beneficial effects:

[0035] A graphite-reinforced elastic compensation ring is press-fitted onto the rotor's outer circumference based on the temperature-gap envelope curve, with a controllable buffer margin. This ring utilizes the graphite material's low thermal expansion coefficient and high elastic modulus to automatically absorb differential expansion between the stator and rotor during temperature fluctuations, ensuring a stable air gap. This passive thermal adaptation mechanism effectively reduces stress concentration caused by thermal expansion, extending the motor's service life.

[0036] Utilizing a six-degree-of-freedom laser alignment system, micro-eccentricity is preset based on the temperature-gap envelope curve, enabling precise alignment of the stator and rotor axes. By optimizing micro-eccentricity, the motor achieves initial geometric equilibrium during assembly, significantly reducing air gap fluctuations caused by temperature changes during operation, improving the symmetry of the magnetic field distribution, and reducing magnetic flux leakage and eddy current losses.

[0037] The collaborative design of a micro-sliding flexible key and piezoelectric displacement plate enables real-time monitoring of displacement and temperature. Two-stage data processing extracts gap variation and thermal hysteresis slip characteristics, and a radial basis function model is used to generate dynamic stability coefficients, which drive the monitoring unit to issue adjustment commands. This sensing mechanism can promptly capture subtle changes in air gap drift, providing high-precision data support for dynamic adjustment.

[0038] By comparing keyway slippage with historical curves of dynamic stability coefficients, the monitoring threshold is corrected and solidified to form an adaptive benchmark. This algorithm optimizes monitoring logic based on actual operating data, ensuring accurate judgment of air gap status during the service phase, reducing false alarms and missed alarms, and improving the reliability of fault prediction.

[0039] Through the threshold solidification after the maiden voyage, the monitoring system can automatically adjust according to the actual working conditions during the service phase to ensure the stability of the air gap. The real-time comparison of the dynamic stability coefficient and the solidification threshold realizes timely early warning of abnormal conditions, significantly reduces the frequency of manual adjustments, and improves the economy of the ship throughout its life cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The figure is a structural schematic diagram of a high-reliability marine stator and rotor assembly method according to the present invention. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] See also Figure 1 The present invention provides a high-reliability marine stator and rotor assembly method, comprising:

[0043] Step 1: Model the thermal expansion of the stator and rotor components through simulation analysis; perform physical testing on samples of the stator and rotor components to measure the actual thermal expansion; combine the simulation analysis data with the physical test data to obtain an accurate data set representing the temperature-air gap relationship; fit a polynomial curve to the accurate data set to generate a temperature-air gap envelope curve; and store the temperature-air gap envelope curve in a database for use in subsequent assembly steps.

[0044] The step 1 includes the following:

[0045] Step 101: Before the assembly process begins, use finite element analysis software to model and calculate the thermal expansion behavior of the stator and rotor. The stator is made of grain-oriented silicon steel, and the rotor contains permanent magnets. These two materials have different thermal expansion coefficients. The modeling temperature range is set from -20°C to 100°C to reflect the thermal expansion characteristics of the motor under different operating conditions. Within this temperature range, the air gap between the stator and rotor is calculated as a function of temperature.

[0046] The specific calculation process is as follows: the change in air gap is derived from the difference in stator and rotor expansion. The stator expansion is determined by multiplying its thermal expansion coefficient, the stator inner diameter as a characteristic length, and the temperature change. The rotor expansion is determined by multiplying its thermal expansion coefficient, the rotor outer diameter as a characteristic length, and the temperature change. The stator inner diameter and rotor outer diameter serve as the respective characteristic lengths, representing the dimensional change benchmark during thermal expansion. Finite element analysis software generates a data set recording the corresponding air gap values ​​at different temperatures, forming a corresponding relationship between temperature and air gap.

[0047] Step 102: Sample testing

[0048] Stator and rotor specimens made of the same materials and structure as the actual motor were fabricated for experimental verification. The specimens were placed in a thermostat, maintained at temperatures between -20°C and 100°C, to simulate the conditions used in the simulation analysis. High-precision measurement equipment, such as a laser rangefinder, was used to measure the dimensional changes of the stator and rotor at different temperatures.

[0049] The specific process involves recording the actual stator inner diameter and rotor outer diameter at each set temperature, comparing them to their initial dimensions, and calculating the temperature-induced expansion of both. The change in air gap is determined by the difference between the stator inner diameter expansion and the rotor outer diameter expansion. The test data, which records the actual air gap change at different temperatures, is used to compare with simulation analysis results to verify the accuracy of the simulation data.

[0050] Integrate the data generated by simulation analysis with the data generated by sample testing to generate more reliable fused data.

[0051] The integration method uses linear interpolation. Specifically, at the same temperature point, a weighted average is calculated for the air gap values ​​obtained from simulation analysis and the air gap values ​​obtained from sample testing. The weighting is determined based on the accuracy of the simulation analysis and sample testing. For example, the weight of the simulation data and the test data can be set to 50%, respectively, indicating that both contribute equally to the fusion result. This weighted average calculation generates a fused set of temperature and air gap correspondence data. This fusion method combines the theoretical predictions of the simulation analysis with the actual measurement results of the sample testing, improving the comprehensiveness and accuracy of the data.

[0052] Step 103: Generate envelope curve

[0053] A polynomial fit is performed on the fused data to generate a continuous curve describing the change in air gap with temperature, called the temperature-gap envelope curve. The fitting process uses a second-order polynomial, and the fitting coefficients are determined using the least squares method. Specifically, the three coefficients of the second-order polynomial are calculated based on the fused data, using temperature as the independent variable and air gap as the dependent variable, so that the fitted curve fits all data points as closely as possible. This curve not only reflects the trend of air gap change with temperature but also defines its possible range of variation through the fitting range. The resulting temperature-gap envelope curve, as a continuous function, fully describes the impact of temperature changes on air gap.

[0054] The temperature-gap envelope curve is recorded in the assembly database as a data table or function for subsequent assembly design and monitoring. The data table contains multiple temperature values ​​and their corresponding air gap values, stored as discrete data points; the function contains the fitting coefficients of a second-order polynomial, stored as a mathematical expression of the continuous relationship. The database also records relevant parameters, including detailed information such as temperature range, initial air gap value, and stator and rotor material parameters. This data provides an accurate reference for thermal expansion compensation design and operational status monitoring during assembly.

[0055] During use, simulation analysis predicts the thermal expansion behavior of the stator and rotor at different temperatures through finite element modeling, providing a theoretical law of air gap change; sample testing verifies the simulation results through actual measurements, making up for the influence of actual factors that may be ignored in theoretical calculations. Data fusion combines the advantages of both through linear interpolation and weighted average methods, improving the reliability of temperature-gap relationship data. The generation of the temperature-gap envelope curve converts discrete data into a continuous function, which is convenient for accurate description and application. The final processing is written to the database to ensure that the data can be systematically called, supporting assembly process optimization and motor performance improvement. This multi-step collaborative technical logic avoids the limitations of relying on a single data source, effectively addresses the problem of air gap drift caused by temperature changes, and thus enhances the stability and durability of the motor.

[0056] Step 2. Select graphite reinforced elastic material to make the compensation ring. This material has low thermal expansion coefficient, high elastic modulus and excellent thermal stability. According to the analysis results of the temperature-gap envelope curve, design the thickness, width and cross-sectional thickness of the compensation ring to ensure that the elastic deformation of the compensation ring is not less than the maximum change of the air gap. Install the compensation ring on the outer surface of the rotor through a press-fitting process, and accurately control the applied radial force to form a preload force. Reserve a buffer margin to cope with the expansion or contraction caused by temperature changes. The buffer margin is determined by multiplying the maximum change of the air gap by a safety factor of 1.2 to 1.5. At the same time, the initial deformation of the compensation ring is controlled by adjusting the radial force.

[0057] The second step includes the following:

[0058] Step 201: Temperature-gap envelope curve analysis

[0059] Extract the temperature-gap envelope curve from the assembly database. This curve reflects the continuous relationship between the air gap and temperature. Determine the motor's operating temperature range, for example, from -20°C to 100°C. Calculate the maximum change in the air gap within this range by finding the maximum and minimum values ​​of the air gap within the temperature range and subtracting the minimum from the maximum. The difference is the maximum change. This maximum change indicates the amplitude of the air gap fluctuation caused by temperature changes and provides a quantitative basis for the subsequent design of the compensation ring. By analyzing the temperature-gap envelope curve, the dynamic characteristics of the air gap can be accurately understood, providing data support for optimizing the thermal compensation structure.

[0060] Graphite-reinforced elastomer is chosen for the compensation ring due to its low thermal expansion coefficient, high elastic modulus, and excellent thermal stability. The low thermal expansion coefficient ensures minimal dimensional change in the compensation ring with temperature fluctuations, while the high elastic modulus ensures sufficient elastic deformation under load. The thermal stability ensures that the material maintains performance even at high temperatures. These properties enable the compensation ring to effectively absorb radial expansion and contraction of the rotor during temperature fluctuations, maintaining air gap stability. Using graphite-reinforced elastomer significantly improves the compensation ring's thermal adaptability and mechanical performance, ensuring reliable motor operation.

[0061] Step 202: Structural design of compensation ring

[0062] The thickness, width, and cross-sectional thickness of the compensation ring are determined based on the rotor's outer diameter and the maximum air gap variation. During design, it is necessary to ensure that the compensation ring's elastic deformation is sufficient to cover the maximum fluctuation in the air gap. The specific calculation method is to determine whether the deformation is less than the maximum variation by analyzing the relationship between the elastic deformation and the maximum air gap variation. The calculation of the elastic deformation involves parameters such as the radial force applied during press-fitting, the thickness of the compensation ring, the elastic modulus of the material, and the cross-sectional area. By adjusting these dimensional parameters, the elastic deformation of the compensation ring meets the design requirements. This structural design method accurately matches the gap fluctuations caused by temperature changes, ensuring the functional performance of the compensation ring.

[0063] A graphite-reinforced elastic compensating ring is press-fitted onto the rotor's outer surface. The radial force applied during the press-fitting process must be precisely controlled to establish an appropriate preload. Once press-fitted, the compensating ring forms a tight fit against the rotor's outer surface. Its elastic deformation absorbs radial expansion of the rotor as temperatures rise, while its elastic recovery maintains air gap stability as temperatures cool. This press-fitting process maintains a preloaded state at room temperature, enabling dynamic adjustment during temperature fluctuations. This precisely controlled press-fitting process not only improves assembly quality but also enhances the compensating ring's adaptability under varying operating conditions.

[0064] Step 203: Reserve controllable buffer margin

[0065] When press-fitting the compensating ring, a controllable buffer is reserved to account for excess expansion or contraction caused by temperature fluctuations. This buffer is calculated by multiplying the maximum air gap change by a safety factor, set between 1.2 and 1.5, to ensure the compensating ring maintains adequate adaptability under extreme temperature conditions. By adjusting the radial force applied during press-fitting, the initial deformation of the compensating ring is controlled, allowing for precise reserve of this buffer. This design enhances the compensating ring's tolerance to abnormal operating conditions and ensures air gap stability across a wide range of temperatures.

[0066] During operation, a thermal compensation structure adapts to temperature fluctuations by analyzing the temperature-gap envelope curve, designing and press-fitting a graphite-reinforced elastic compensation ring, and retaining a controllable buffer margin. The low thermal expansion coefficient and high elastic modulus of the graphite-reinforced elastic material effectively absorb differential expansion between the stator and rotor, maintaining air gap stability. The precise implementation of the press-fitting process and the provision of a buffer margin further enhance the compensation ring's adaptability to extreme temperature conditions. This design significantly improves the motor's thermal stability, avoiding the risk of magnetic field imbalance and thermal failure caused by air gap fluctuations, thereby enhancing the operational reliability of the marine motor.

[0067] During the motor assembly process, step three utilizes a six-degree-of-freedom laser alignment system to precisely pre-determine the micro-eccentricity of the stator and rotor axis based on the temperature-gap envelope curve, and the relevant data is synchronously recorded in the assembly control table. The following text describes the formulas involved in the specific processing technology logic of step three, and further explains the reasons and benefits of each technical feature. The description is divided into several sub-steps, each paragraph corresponding to a sub-step, ensuring clear logic and contextual coherence, suitable for use in the invention specification.

[0068] Step 3: extracting a temperature-gap envelope curve from the assembly database, wherein the temperature-gap envelope curve describes the continuous change relationship between the air gap and the temperature; determining the operating temperature range of the motor, and calculating the maximum change of the air gap within the operating temperature range; calculating the average value of the air gap within the operating temperature range as a reference for micro-eccentricity design; determining the micro-eccentricity through an optimization method to minimize the deviation between the actual air gap and the ideal air gap within the operating temperature range; deploying a six-degree-of-freedom laser alignment system to measure and adjust the position parameters of the stator and rotor in real time to ensure that the offset between the stator and rotor axes reaches the optimal micro-eccentricity; recording the adjusted position data, wherein the position data includes the micro-eccentricity and the axis coordinates, generating an assembly control table and storing it in the assembly database;

[0069] The step three includes the following:

[0070] Step 301: Extract the temperature-gap envelope curve from the assembly database

[0071] The temperature-gap envelope curve describes the continuous relationship between air gap and temperature. After determining the motor's operating temperature range, the average air gap value within that range is calculated. This calculation method accumulates the continuous values ​​of the air gap's temperature variation within the operating temperature range and then divides this cumulative sum by the temperature span of the operating temperature range to obtain the average air gap value. This average air gap value serves as a basic reference for subsequent micro-eccentricity design, ensuring that the air gap maintains overall stability despite temperature fluctuations after assembly.

[0072] By calculating the average air gap value, a comprehensive representation of air gap variations within the operating temperature range can be obtained. This reflects the typical level of air gap during temperature fluctuations and provides a stable reference point for micro-eccentricity design. This method helps reduce air gap non-uniformity caused by temperature changes, thereby improving the smoothness and efficiency of motor operation.

[0073] Step 302: Determine the micro-eccentricity by optimization method

[0074] The optimization goal is to minimize the deviation between the actual and ideal air gaps within the operating temperature range. The specific process involves finding a suitable axis offset that minimizes the cumulative sum of the absolute differences between the actual and ideal air gaps within the operating temperature range. This optimization problem is solved using the gradient descent method. By iteratively adjusting the offset, the optimal solution that minimizes the sum of the deviations is gradually approached, ultimately yielding the optimal micro-eccentricity.

[0075] When in use, the design of optimizing the micro-eccentricity can ensure that the actual air gap is as close as possible to the ideal value under different temperature conditions, thereby maintaining the stability of the air gap. This method reduces the impact of temperature changes on motor performance by quantifying and minimizing the deviation, thereby improving the motor's operating reliability and service life.

[0076] Step 303: Deploy a six-degree-of-freedom laser alignment system for position adjustment

[0077] The six-degree-of-freedom laser alignment system measures and controls the stator and rotor position parameters, including axis coordinates and angular deviation, in real time. During alignment, the system precisely controls the stator-rotor axis offset based on the optimal micro-eccentricity value, ensuring that the offset is consistent with the optimized result. Once alignment is complete, the stator and rotor axis positions meet the preset micro-eccentricity requirements.

[0078] The 6-DOF laser alignment system offers high-precision measurement and adjustment capabilities, effectively eliminating geometric errors during assembly. By precisely achieving the optimal micro-eccentricity, it ensures the relative position between the stator and rotor meets design requirements, thereby improving assembly accuracy and motor operation stability.

[0079] Step 304: Generate assembly control table and record data synchronously

[0080] After adjustment, the final position parameters of the stator and rotor are recorded, including key information such as micro-eccentricity and axis coordinates. This data is linked with relevant information such as the temperature-gap envelope curve to form a complete data set and stored in the assembly database. The assembly control table serves as a record carrier, preserving the adjusted position data and design parameters for subsequent use.

[0081] Systematically recording position parameters and design data ensures traceability and consistency throughout the assembly process. This data management approach facilitates subsequent quality inspections and performance analysis, while providing reliable reference information for motor maintenance and enhancing the standardization and controllability of the production process.

[0082] In summary, Step 3 achieves precise presetting of the stator and rotor axis and effective data management through a series of technical measures, including extracting data from the temperature-gap envelope curve, optimizing the micro-eccentricity design, adjusting the position using a six-degree-of-freedom laser alignment system, and generating an assembly control table. These technical features work together to ensure the stability of the motor's air gap under different temperature conditions, improving assembly quality and operating performance, and embodying the integrated application of scientific methods and advanced equipment in motor manufacturing.

[0083] Step 4: Install a micro-sliding flexible key made of high-strength alloy steel and coated with a wear-resistant coating on the keyway of the motor, and embed a piezoelectric displacement plate made of piezoelectric ceramic material inside the keyway to collect displacement and temperature signals in real time at a frequency of 100 times per second; perform Fourier transform on the displacement signal to extract low-frequency components in the frequency range of 0 to 10 Hz, which are defined as gap change characteristics; perform time domain analysis on the temperature and displacement signals to calculate the thermal hysteresis slip characteristics as the ratio of the temperature change rate to the displacement change rate; input the gap change characteristics and thermal hysteresis slip characteristics into a pre-trained radial basis function neural network model to output a dynamic stability control coefficient; the monitoring unit compares the dynamic stability control coefficient with a preset threshold, generates an adjustment instruction, and transmits it to the control center via a wireless communication module;

[0084] The step 4 includes the following contents:

[0085] Step 401: Installation and function of the micro-sliding flexible key

[0086] A micro-sliding flexible key is installed in the motor keyway. Made of high-strength alloy steel and coated with a wear-resistant coating, it improves durability and corrosion resistance, making it suitable for the salt spray and hot, humid environment of the sea. The micro-sliding flexible key has an elastic design, allowing it to slide slightly when stress is generated in the rotor due to thermal expansion or hull bending and torsion. The amount of slippage has been calibrated experimentally, and the relationship between temperature and mechanical load has been predetermined. The installation of the micro-sliding flexible key reduces stress concentration, protects the keyway structure, and provides physical conditions for the subsequent collection of displacement data. Its design ensures the stability of the motor in extreme environments and provides reliable operational support for the monitoring system. Through its elastic design and wear-resistant coating, the micro-sliding flexible key reduces damage to the keyway caused by stress concentration, improves the durability of the motor in harsh environments, provides a stable hardware foundation for displacement and temperature monitoring, and enhances the reliability of the system.

[0087] Step 402: Embedding of piezoelectric displacement plate and data acquisition

[0088] Embedded within the micro-sliding flexible key is a piezoelectric displacement plate made of piezoelectric ceramic material, which converts mechanical displacement into electrical signals. This plate collects the key's displacement and temperature signals in real time, at a rate of 100 times per second to capture the subtle effects of rapid air gap changes and temperature fluctuations. The collected displacement and temperature signals are sampled and stored at high frequency, ensuring data accuracy and real-time performance, providing high-precision input for subsequent data processing.

[0089] When in use, the piezoelectric displacement plate uses the piezoelectric effect to directly convert displacement and temperature changes into electrical signals. The high-frequency acquisition method ensures the time resolution of the data, can accurately reflect the dynamic changes in the motor's operating status, and provides reliable data support for subsequent analysis.

[0090] Step 403: First level data processing: extracting gap variation characteristics

[0091] The collected displacement signal is subjected to frequency domain analysis. Specifically, the displacement signal is converted into a frequency domain signal through Fourier transform, from which a low-frequency component with a frequency range of 0 to 10 Hz is extracted. This component reflects the slow change of the air gap and is defined as the gap change characteristic quantity. The calculation method of the gap change characteristic quantity is as follows: the displacement signals of multiple piezoelectric displacement plates (for example, 4) installed in the four directions of the micro-sliding flexible key are weighted averaged, and the weights are determined by experimental calibration to comprehensively reflect the change trend of the air gap. Extracting low-frequency components through Fourier transform can filter out high-frequency noise, highlight the actual change trend of the air gap, and improve the validity of the data. The weighted average method integrates the measurement results of multiple piezoelectric displacement plates, enhances the reliability and representativeness of the gap change characteristic quantity, and ensures that the data processing results accurately reflect the motor status.

[0092] Step 404: Second level data processing: extracting thermal hysteresis slip characteristics

[0093] Time-domain analysis is performed on the temperature and displacement signals to calculate the lag time between temperature changes and displacement changes. The thermal hysteresis-slip characteristic is defined as the ratio of the temperature change rate to the displacement change rate, which is used to reflect the effect of thermal expansion on displacement. The temperature change rate is calculated by dividing the temperature difference between consecutive time points by the time interval, and the displacement change rate is calculated by dividing the displacement difference between consecutive time points by the time interval. When the temperature change rate approaches zero, the thermal hysteresis-slip characteristic is set to zero to avoid numerical anomalies in the calculation. The thermal hysteresis-slip characteristic reveals the coupling effect of thermal expansion and mechanical deformation by quantifying the dynamic relationship between temperature changes and displacement changes. The time-domain analysis method can capture the response characteristics of temperature and displacement in real time, improve the sensitivity and accuracy of the monitoring system, and provide key information for the dynamic evaluation of the motor status.

[0094] The gap variation and thermal hysteresis slip characteristics are fed into a pre-trained radial basis function neural network model, which outputs a dynamic stability coefficient. The radial basis function neural network uses a Gaussian function as an activation function and calculates the dynamic stability coefficient by combining weights and center positions. Model training is based on historical data, including records of temperature, mechanical load, and air gap changes, ensuring that the model can reflect the nonlinear relationships between these variables.

[0095] Radial basis function neural networks excel at handling nonlinear problems and can quickly generate dynamic stability coefficients, providing an efficient means for real-time feedback on motor status. Their adaptive learning capabilities allow the model to be continuously optimized based on actual operating data, improving the accuracy and response speed of dynamic control.

[0096] Step 405: Generate an adjustment instruction for the monitoring unit

[0097] The monitoring unit compares the dynamic stability coefficient with a preset threshold, which is determined in step five based on motor operating requirements. Based on the comparison result, an adjustment command is generated: if the absolute value of the dynamic stability coefficient exceeds the preset threshold, an alarm is triggered and manual adjustment is recommended; if the absolute value of the dynamic stability coefficient does not exceed the preset threshold, the current operating state is maintained. The adjustment command is transmitted to the control center via a wireless communication module, ensuring real-time transmission and response.

[0098] By comparing the dynamic stability coefficient with a preset threshold, the system automatically monitors the motor's operating status and provides warnings of abnormalities, effectively preventing failures caused by abnormal air gap variations. The use of a wireless communication module improves the flexibility and efficiency of command transmission, ensuring reliable system operation in extreme environments.

[0099] The technical logic of step four achieves real-time monitoring of the motor's air gap and temperature through the collaborative work of a micro-sliding flexible key and a piezoelectric displacement plate. The two-level data processing method extracts the gap change characteristic quantity and the thermal hysteresis slip characteristic quantity, and combines the radial basis function neural network model to generate a dynamic stability control coefficient, driving the monitoring unit to issue adjustment instructions. This design improves the sensitivity and accuracy of the monitoring system, reduces the need for manual intervention through automated control, and significantly enhances the stability and reliability of the motor. In the extreme environment of hot and cold cycles and mechanical load fluctuations at sea, this technical logic ensures the stable operation of marine motors, extends their service life, and reduces maintenance costs.

[0100] Step 5. During the maiden voyage of the ship, the slip amount of the micro-sliding flexible key is continuously monitored at a frequency of once per minute using a piezoelectric displacement plate, and the dynamic stability control coefficient generated by the radial basis function model is recorded at the same time. The slip amount and dynamic stability control coefficient collected during the maiden voyage are subjected to time series analysis to generate a historical curve, and the maximum value of the slip amount and the maximum deviation of the dynamic stability control coefficient are determined, and then the monitoring threshold is corrected. The correction method is to multiply the maximum deviation of the dynamic stability control coefficient by the adjustment coefficient 1.5 and the maximum value of the slip amount by the adjustment coefficient 0.01, and then add the result to the initial monitoring threshold. The corrected monitoring threshold is solidified as the air gap status reference value during the service stage. During the service period, the monitoring unit compares the dynamic stability control coefficient with the solidified monitoring threshold in real time to determine whether the air gap status is abnormal.

[0101] The step five includes the following:

[0102] The technical logic of step five aims to optimize the monitoring threshold of the air gap status through the analysis of the measured data during the maiden voyage, and solidify it as the baseline value during the service life of the motor, so as to achieve real-time monitoring of air gap drift and abnormal warning.

[0103] Step 501: Data collection for the maiden voyage

[0104] During the ship's maiden voyage, the slip of the micro-sliding flexible key was continuously monitored using a piezoelectric displacement plate, while the dynamic stability coefficient generated by the radial basis function model was recorded. The slip refers to the tiny displacement data generated by the keyway during operation, and the dynamic stability coefficient is a parameter derived by combining the gap change characteristic quantity and the thermal hysteresis slip characteristic quantity, which is used to characterize the stability of the air gap state. The data acquisition frequency is set to once per minute to ensure that the dynamic response characteristics of the motor in actual sea operation can be captured. Through high-frequency data acquisition, the real-time dynamic changes of the motor under complex working conditions at sea can be fully recorded, providing detailed and reliable data support. This method can ensure that the monitoring system has sufficient accuracy and timeliness in measuring the slip and dynamic stability coefficient, providing a solid foundation for subsequent analysis and threshold optimization.

[0105] Step 502: Generate and analyze historical curves

[0106] The slip and dynamic stability coefficient data collected during the maiden voyage were analyzed over time, generating their respective historical curves. For the slip historical curve, the maximum slip value during the maiden voyage was determined by observing its trend over temperature and load. For the dynamic stability coefficient historical curve, the fluctuation amplitude and response characteristics were evaluated by analyzing its value changes over time. The average value and maximum deviation of the dynamic stability coefficient were calculated. The maximum deviation refers to the maximum difference in the dynamic stability coefficient from the average value during the maiden voyage.

[0107] Generating and analyzing historical curves can visually demonstrate the motor's air gap behavior during actual operation, helping to identify abnormal fluctuations or peaks in slip and dynamic stability coefficients. This analysis provides a data basis for optimizing monitoring thresholds, enabling the system to better adapt to actual operating conditions and improving the pertinence and accuracy of monitoring.

[0108] Step 503: Correction of monitoring threshold

[0109] The initial monitoring threshold is a fixed value preset during the design phase, while the revised monitoring threshold is adjusted based on measured data during the maiden flight. The specific correction method is as follows: first, the maximum deviation of the dynamic stability coefficient is multiplied by a preset adjustment factor, such as 1.5, to reflect extreme fluctuations in the air gap state; then, the maximum slip value is multiplied by another preset adjustment factor, such as 0.01, to reflect the peak impact of the keyway displacement; finally, the above two calculation results are added together and added to the initial monitoring threshold to obtain the revised monitoring threshold.

[0110] By incorporating the maximum deviation of the dynamic stability coefficient and the maximum slip into the threshold correction process, the fluctuating characteristics of the air gap state and the peak characteristics of the keyway displacement during the maiden voyage can be comprehensively reflected. This correction method makes the monitoring threshold more closely aligned with actual operating conditions at sea, thereby improving the sensitivity and accuracy of the monitoring system and ensuring that abnormal conditions can be detected in a timely manner.

[0111] Step 504: Threshold Curing and Application

[0112] The corrected monitoring threshold is solidified as the reference value for the air gap state during the motor's service life. During the motor's service phase, the monitoring unit calculates the value of the dynamic stability coefficient in real time and compares it with the solidified monitoring threshold. If the absolute value of the dynamic stability coefficient exceeds the solidified monitoring threshold, the air gap state is determined to be abnormal, triggering an alarm and prompting manual intervention. If the absolute value of the dynamic stability coefficient does not exceed the solidified monitoring threshold, the air gap state is considered normal and the motor continues to maintain its current operating state. Solidifying the corrected monitoring threshold as the reference value and applying it to real-time monitoring during the service phase ensures that the monitoring system maintains continued sensitivity to air gap drift. This method provides timely early warning of abnormal conditions and effectively prevents potential failures caused by air gap drift, thereby improving the reliability and stability of motor operation.

[0113] During use, the technical logic of step five optimizes the monitoring threshold of the air gap status through analysis of measured data during the maiden voyage, and solidifies it as a baseline value during service, ensuring that the monitoring system can adapt to the complexity of actual working conditions at sea. The historical curve analysis method combines the timing characteristics of the slip and dynamic stability coefficient, comprehensively considers the impact of external factors such as temperature and load on the air gap status, and provides a scientific basis for threshold correction. The threshold correction process makes the monitoring logic more accurate and sensitive by introducing the maximum deviation of the dynamic stability coefficient and the maximum value of the slip. The application of the solidified monitoring threshold in the service stage realizes real-time monitoring of air gap drift and abnormal warning, which significantly improves the operating stability and durability of marine motors.

[0114] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0115] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0116] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is only for some logical functions. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0117] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0118] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A high-reliability marine stator and rotor assembly method, characterized by: include, Before assembly, the temperature-gap envelope curve is generated through the fusion of finite element simulation and sample testing and written into the database as the baseline for thermal compensation design; According to the temperature-clearance envelope curve, a graphite-reinforced elastic compensation ring is press-fitted on the outer circle of the rotor and a controllable buffer margin is reserved; Using a six-degree-of-freedom laser alignment system, the micro-eccentricity of the stator and rotor axis is preset according to the temperature-clearance envelope curve, and the relevant data is written into the assembly control table; A micro-sliding flexible key is installed in the keyway and a piezoelectric displacement plate is embedded to collect displacement and temperature data. The gap variation characteristic and thermal hysteresis slip characteristic are extracted through two-stage processing. These are then input into a radial basis function model in parallel to generate dynamic stability coefficients, which drive the monitoring unit to issue adjustment commands. By comparing the historical curves of keyway slip and dynamic stability coefficient, the monitoring threshold is corrected and solidified as the air gap status benchmark during the service phase.

2. A high-reliability marine stator and rotor assembly method according to claim 1, characterized in that: Modeling the thermal expansion of stator and rotor components through simulation analysis and physically testing samples of stator and rotor components to measure the actual thermal expansion; combining the simulation analysis data with the physical test data to obtain an accurate data set representing the temperature-air gap relationship; A polynomial curve is fitted to the precise data set to generate a temperature-air gap envelope curve, and the temperature-air gap envelope curve is stored in a database.

3. A high-reliability marine stator and rotor assembly method according to claim 2, characterized in that: Graphite reinforced elastic material is selected to make the compensation ring. According to the analysis results of the temperature-gap envelope curve, the thickness, width and cross-sectional thickness of the compensation ring are designed so that the elastic deformation of the compensation ring is not less than the maximum change of the air gap.

4. A high-reliability marine stator and rotor assembly method according to claim 3, characterized in that: The compensation ring is installed on the outer surface of the rotor through a press-fit process, and the radial force applied is precisely controlled to form a preload; A buffer margin is reserved to cope with expansion or contraction caused by temperature changes. The buffer margin is determined by multiplying the maximum change in the air gap by a safety factor of 1.2 to 1.

5. The initial deformation of the compensation ring is controlled by adjusting the radial force.

5. The high-reliability marine stator and rotor assembly method according to claim 4, characterized in that: Extracting a temperature-gap envelope curve from an assembly database, wherein the temperature-gap envelope curve describes a continuous variation relationship of the air gap with temperature; Determine the operating temperature range of the motor and calculate the maximum change in the air gap within the operating temperature range; The average value of the air gap within the operating temperature range is calculated as the basis for the micro-eccentricity design.

6. A high-reliability marine stator and rotor assembly method according to claim 5, characterized in that: Determine the micro-eccentricity by an optimization method so as to minimize the deviation between the actual air gap and the ideal air gap within the operating temperature range; A six-degree-of-freedom laser alignment system is deployed to measure and adjust the position parameters of the stator and rotor in real time to ensure that the offset between the stator and rotor axis reaches the optimal micro-eccentricity; the adjusted position data, which includes the micro-eccentricity and axis coordinates, is recorded, and an assembly control table is generated and stored in the assembly database.

7. A high-reliability marine stator and rotor assembly method according to claim 6, characterized in that: A micro-sliding flexible key made of high-strength alloy steel and coated with a wear-resistant coating is installed in the keyway of the motor. A piezoelectric displacement piece made of piezoelectric ceramic material is embedded inside to collect displacement and temperature signals in real time at a frequency of 100 times per second. The displacement signal is subjected to Fourier transform to extract the low-frequency component in the frequency range of 0 to 10 Hz, which is defined as the gap change characteristic.

8. The high-reliability marine stator and rotor assembly method according to claim 7, characterized in that: Perform time-domain analysis on the temperature and displacement signals, and calculate the thermal hysteresis-slip characteristic as the ratio of the temperature change rate to the displacement change rate. Input the gap change characteristic and the thermal hysteresis-slip characteristic into a pre-trained radial basis function neural network model, and output the dynamic stability control coefficient. The monitoring unit compares the dynamic stability control coefficient with the preset threshold, generates an adjustment instruction and transmits it to the control center through the wireless communication module.

9. A high-reliability marine stator and rotor assembly method according to claim 8, characterized in that: The piezoelectric displacement plate is used to continuously monitor the slip of the micro-sliding flexible key at a frequency of once per minute, and the dynamic stability coefficient generated by the radial basis function model is recorded at the same time. By performing a time series analysis on the slip and dynamic stability coefficient collected during the maiden voyage, a historical curve is generated to determine the maximum slip and the maximum deviation of the dynamic stability coefficient, and to correct the monitoring threshold.

10. A high-reliability marine stator and rotor assembly method according to claim 9, characterized in that: The method for correcting the monitoring threshold is as follows: multiply the maximum deviation of the dynamic stability coefficient by the adjustment coefficient of 1.5, add the maximum value of the slip amount by the adjustment coefficient of 0.01, and then add them to the initial monitoring threshold; The corrected monitoring threshold is solidified as the air gap status reference value during the service phase, and during the service phase, the monitoring unit compares the dynamic stability control coefficient with the solidified monitoring threshold in real time to determine whether the air gap status is abnormal.

Images