An optimal preload analysis method and system for electric spindle

Abstract

The present invention relates to the technical field of preload analysis, and is a method and system for analyzing the optimal preload for an electric spindle, comprising: performing rotational vibration balancing on a running electric spindle to obtain a balanced electric spindle, performing stiffness and temperature measurement on the balanced electric spindle to obtain a spindle rotational stiffness set and a spindle change temperature set, performing acoustic wave measurement on the balanced electric spindle using a preload measurement unit to obtain an acoustic wave preload set and a piezoelectric preload set, performing preload curve fitting on the acoustic wave preload set and the piezoelectric preload set, respectively, to obtain an acoustic wave preload curve and a piezoelectric preload curve, identifying a candidate preload line segment set and confirming a candidate test environment group set according to the acoustic wave preload curve and the piezoelectric preload curve, and constructing an optimal preload table based on the candidate preload line segment set and the candidate test environment group set. The present invention can improve the accuracy and efficiency of the optimal preload analysis of the electric spindle.

Description

Technical Field

[0001] The invention relates to the technical field of preload analysis, and in particular to an optimal preload analysis method and system for an electric spindle. Background Art

[0002] The electric spindle is a device that integrates an electric motor and a machine tool spindle. It plays a vital role in the field of modern mechanical processing. The preload applied to the electric spindle can eliminate the bearing clearance in the electric spindle, thereby increasing the stiffness of the electric spindle. Excessive preload will cause the temperature of the electric spindle to rise and reduce the service life of the electric spindle. Therefore, the optimal preload analysis of the electric spindle is of great significance in practical applications.

[0003] At present, the optimal preload force analysis of the electric spindle is mainly achieved through the weight coefficient method. Although this method can achieve the optimal preload force analysis of the electric spindle, it only calculates the weight coefficients of the parameters that affect the preload force of the electric spindle, which makes the calculated optimal preload force not necessarily meet the actual required preload force, reducing the accuracy of the optimal preload force analysis. At the same time, repeated calculations are required for different electric spindle operating environments, which reduces the efficiency of the optimal preload force analysis. Summary of the invention

[0004] The present invention provides an optimal preload analysis method and system for an electric spindle, the main purpose of which is to improve the accuracy and efficiency of the optimal preload analysis of the electric spindle.

[0005] To achieve the above object, the present invention provides an optimal preload force analysis method for an electric spindle, comprising:

[0006] Receiving a preload force analysis instruction, setting an initial spindle speed based on the preload force analysis instruction, starting a pre-built electric spindle to be tested based on the initial spindle speed, and obtaining a running electric spindle, wherein the speed of the running electric spindle is the initial spindle speed;

[0007] Performing rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle;

[0008] Performing a rotational stiffness test on a balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and measuring a spindle temperature change set of the balanced electric spindle based on the real-time measurement time set;

[0009] Starting a pre-built preload force measurement unit, wherein the preload force measurement unit includes: an acoustic wave measurement unit and a piezoelectric measurement unit, wherein the acoustic wave measurement unit is an ultrasonic probe, and the piezoelectric measurement unit is a piezoelectric sensor;

[0010] Using an acoustic wave measurement unit to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set, wherein the acoustic wave measurement unit is arranged on both sides of the balanced electric spindle;

[0011] Using a piezoelectric measuring unit to perform piezoelectric measurement of the preload force of the balancing electric spindle to obtain a piezoelectric preload force set, wherein the piezoelectric measuring unit is placed at the connection between the bearing and the spindle of the balancing electric spindle;

[0012] According to the real-time measurement time set, preload force curve fitting is performed on the acoustic wave preload force set and the piezoelectric preload force set respectively to obtain an acoustic wave preload force curve and a piezoelectric preload force curve;

[0013] According to the acoustic preload curve and the piezoelectric preload curve, a candidate preload line segment set is identified and a candidate test environment group set is respectively confirmed in the spindle rotation stiffness set and the spindle change temperature set, wherein the candidate test environment group set includes: a candidate change temperature group set and a candidate rotation stiffness group set;

[0014] Based on the candidate preload line segment set and the candidate test environment group set, an optimal preload table is constructed, and based on the optimal preload table, an optimal preload analysis of the electric spindle is completed.

[0015] Optionally, performing rotational vibration balancing on a running electric spindle to obtain a balanced electric spindle comprises:

[0016] Performing area division in the running electric spindle to obtain a set of areas to be balanced, extracting the areas to be balanced in the set of areas to be balanced in turn and setting the balancing accuracy level, wherein each area to be balanced in the set of areas to be balanced has a displacement sensor;

[0017] Measuring the regional offset mass and the regional rotation radius of the area to be balanced, wherein the regional rotation radius is the distance between the center point of the area to be balanced and the rotation center of the rotor in the running electric spindle, calculating the regional balance amount and the regional controllable balance amount of the area to be balanced according to the regional offset mass and the regional rotation radius, and judging whether the regional balance amount is less than the regional controllable balance amount;

[0018] If the area to be balanced amount is not less than the area controllable balance amount, the vibration displacement component of the displacement sensor is obtained, wherein the vibration displacement component includes: radial vibration displacement and vertical vibration displacement, and the azimuth angle to be balanced is determined according to the vibration displacement component, wherein the azimuth angle to be balanced is expressed as:

[0019] ;

[0020] in, represents the azimuth to be balanced, represents the inverse tangent function, represents the vertical vibration displacement, Indicates radial vibration displacement, reduces the load of the area to be balanced according to the azimuth angle to be balanced and the preset unit load mass, obtains an adjusted balancing area, updates the area to be balanced using the adjusted balancing area, and returns to the step of measuring the area offset mass and the area rotation radius of the area to be balanced;

[0021] If the area to be balanced amount is less than the area controllable balance amount, the area to be balanced is recorded as a balance area, the balance areas are summarized to obtain a balance area set, and the running electric spindle is updated using the balance area set to obtain a balanced electric spindle.

[0022] Optionally, the calculating, according to the regional offset mass and the regional rotation radius, the regional balance amount and the regional controllable balance amount of the region to be balanced includes:

[0023] According to the regional offset mass and the regional rotation radius, the regional balance amount is calculated, wherein the regional balance amount is expressed as:

[0024] ;

[0025] in, Indicates the area to be balanced. represents the quality of regional migration, Indicates the area rotation radius;

[0026] The static area quality of the area to be balanced is obtained, and the regional controllable balancing amount of the area to be balanced is set according to the initial spindle speed, the regional rotation radius, the balancing accuracy level and the static area quality using the following formula:

[0027] ;

[0028] in, represents the controllable balance of the area, represents the static area quality, Indicates the balancing accuracy level, represents pi, Indicates the initial spindle speed.

[0029] Optionally, the performing of a rotational stiffness test on the balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set includes:

[0030] Using the multiple displacement sensors to measure the initial vibration displacement set of the balanced electric spindle, and recording the current initial load mass and the real-time measurement time, wherein the number of initial vibration displacements in the initial vibration displacement set is the same as the number of displacement sensors in the multiple displacement sensors;

[0031] According to the unit load mass, the initial load mass of the balanced electric spindle is increased to obtain a loaded electric spindle, wherein the position where the load mass is increased is a load device connected to the balanced electric spindle;

[0032] Acquire the current load speed of the loaded electric spindle, increase the speed of the current load speed, and when the current load speed is equal to the initial spindle speed, stop increasing the speed of the current load speed and measure the vibration displacement of the loaded electric spindle to obtain a target vibration displacement set;

[0033] Acquire the current running load mass, and identify the maximum initial displacement and the maximum target displacement in the initial vibration displacement set and the target vibration displacement set, respectively, wherein the maximum initial displacement and the maximum target displacement are both vector synthetic displacements;

[0034] Calculating the spindle rotation stiffness according to the maximum initial displacement, the maximum target displacement and the running load mass;

[0035] Using the load electric spindle and the running load mass to update the balanced electric spindle and the initial load mass respectively, and returning to the step of increasing the load mass of the initial load mass of the balanced electric spindle according to the unit load mass, until the spindle rotation stiffness quantity obtained is not less than the preset reference stiffness quantity;

[0036] The spindle rotation stiffness and the real-time measurement time are respectively summarized to obtain a spindle rotation stiffness set and a real-time measurement time set.

[0037] Optionally, the calculating the spindle rotation stiffness according to the maximum initial displacement, the maximum target displacement and the running load mass includes:

[0038] Identify the maximum difference angle between the maximum initial displacement and the maximum target displacement, and calculate the spindle rotation stiffness according to the initial spindle speed, the maximum difference angle, the running load mass, the maximum initial displacement and the maximum target displacement, wherein the spindle rotation stiffness is expressed as:

[0039] ;

[0040] in, represents the spindle rotation stiffness, Indicates the running load mass, represents the maximum initial displacement, represents the maximum target displacement, represents the absolute value symbol, represents the cosine function, Indicates the maximum difference angle.

[0041] Optionally, the using an acoustic wave measurement unit to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set includes:

[0042] Acquiring the acoustic-elastic coefficient of the acoustic-wave measurement unit, wherein the acoustic-elastic coefficient includes: the acoustic-elastic coefficient of a transverse wave and the acoustic-elastic coefficient of a longitudinal wave;

[0043] Confirming an effective rotational position in the balanced electric spindle, identifying the total spindle length of the balanced electric spindle and the effective rotational length of the effective rotational position, respectively, and obtaining a measurement contact area between the acoustic wave measurement unit and the balanced electric spindle;

[0044] The following operations are performed for each real-time measurement moment in the real-time measurement moment set:

[0045] Based on the real-time measurement moment, the acoustic wave measuring unit is used to perform acoustic wave monitoring on the balanced electric spindle, wherein the acoustic wave monitoring process is that the acoustic wave measuring unit emits ultrasonic waves to the balanced electric spindle and records the propagation speed of the ultrasonic waves when propagating in the balanced electric spindle;

[0046] Recording the sound wave propagation speed of the ultrasonic wave when it propagates in the balanced electric spindle during the sound wave monitoring process, wherein the sound wave propagation speed includes: longitudinal wave propagation speed and shear wave propagation speed;

[0047] According to the acoustic wave propagation velocity, acoustic wave acoustoelastic coefficient, effective rotation length, total spindle length and measured contact area, the acoustic wave preload force is calculated using the following formula:

[0048] ;

[0049] in, Indicates the acoustic preload force, represents the total length of the main axis, represents the shear wave propagation speed, Represents the measured contact area, represents the effective rotation length, represents the shear wave acoustoelastic coefficient, represents the longitudinal wave acoustoelastic coefficient, represents the propagation speed of longitudinal waves;

[0050] The acoustic wave preload forces are aggregated to obtain an acoustic wave preload force set.

[0051] Optionally, the piezoelectric measurement of the preload force of the balanced electric spindle by using a piezoelectric measurement unit to obtain a piezoelectric preload force set includes:

[0052] Identifying a plurality of piezoelectric sensors of the piezoelectric measuring unit, wherein the number of the piezoelectric sensors is manually set, and the plurality of piezoelectric sensors are evenly mounted on the side surface of the bearing in the balancing electric spindle;

[0053] The following operations are performed for each real-time measurement moment in the real-time measurement moment set:

[0054] Starting the piezoelectric measuring unit and using the piezoelectric measuring unit to measure the pressure of the balancing electric spindle to obtain an original measured pressure set, wherein the number of original measured pressures in the original measured pressure set is the same as the number of piezoelectric sensors in the piezoelectric measuring unit;

[0055] Identifying a first maximum pressure and a second maximum pressure in the original measured pressure set, and identifying a first measurement position and a second measurement position corresponding to the first maximum pressure and the second maximum pressure, respectively;

[0056] Calculating the piezoelectric azimuth angles at the first measurement position and the second measurement position, and determining whether the piezoelectric azimuth angle is less than a preset standard azimuth angle;

[0057] If the piezoelectric azimuth angle is not less than the standard azimuth angle, the piezoelectric preload force is calculated according to the first maximum pressure, the second maximum pressure and the piezoelectric azimuth angle, wherein the piezoelectric preload force is expressed as:

[0058] ;

[0059] in, represents the piezoelectric preload, Indicates the first extreme pressure, Indicates the second greatest pressure, represents the piezoelectric azimuth;

[0060] If the piezoelectric azimuth angle is smaller than the standard azimuth angle, the first maximum pressure is recorded as the piezoelectric preload force; and the piezoelectric preload forces are summarized to obtain a piezoelectric preload force set.

[0061] Optionally, the identifying the candidate preload line segment set and respectively confirming the candidate test environment group set in the spindle rotation stiffness set and the spindle temperature change set include:

[0062] Performing line segment division on the acoustic wave preload force curve to obtain an acoustic wave line segment set, and identifying an acoustic wave preload force coefficient set and an acoustic wave time period set of the acoustic wave line segment set, wherein the acoustic wave preload force coefficient is the slope of the acoustic wave line segment, and the acoustic wave time period is the horizontal coordinate range of the acoustic wave line segment;

[0063] Dividing the piezoelectric preload force curve into segments according to the acoustic wave time period set to obtain a piezoelectric line segment set, and identifying a piezoelectric preload force coefficient set of the piezoelectric line segment set;

[0064] Extracting the acoustic wave preload coefficient and the piezoelectric preload coefficient from the acoustic wave preload coefficient set and the piezoelectric preload coefficient set respectively, and calculating the coefficient difference between the acoustic wave preload coefficient and the piezoelectric preload coefficient;

[0065] Determine whether the coefficient difference is less than a preset standard deviation;

[0066] If the coefficient difference is less than the standard deviation, respectively identifying candidate acoustic wave segments and candidate piezoelectric line segments of the acoustic wave preload coefficient and the piezoelectric preload coefficient, averaging the candidate acoustic wave segments and candidate piezoelectric line segments to obtain candidate preload line segments;

[0067] Identify candidate acoustic wave time periods of candidate preload force line segments in the acoustic wave time period set, and confirm candidate temperature change groups and candidate rotational stiffness groups in the spindle temperature change set and spindle rotational stiffness set based on the candidate acoustic wave time periods;

[0068] The candidate preload line segments, candidate change temperature groups and candidate rotational stiffness groups are respectively summarized to obtain a candidate preload line segment set, a candidate change temperature group set and a candidate rotational stiffness group set.

[0069] Optionally, constructing an optimal preload table based on the candidate preload line segment set and the candidate test environment group set includes:

[0070] Extracting candidate preload line segments, candidate change temperature groups and candidate rotational stiffness groups in sequence from the candidate preload line segment set, candidate change temperature group set and candidate rotational stiffness group set respectively;

[0071] Identifying the minimum change temperature and the maximum rotational stiffness in the candidate change temperature group and the candidate rotational stiffness group, respectively, and identifying the minimum temperature moment and the maximum stiffness moment of the minimum change temperature and the maximum rotational stiffness, respectively;

[0072] Based on the minimum temperature moment and the maximum stiffness moment, confirming the temperature mapping preload and the stiffness mapping preload in the candidate preload line segment, calculating the median preload of the temperature mapping preload and the stiffness mapping preload, and recording the median preload as the optimal preload;

[0073] Key-pairing the optimal preload force, the candidate temperature change group and the candidate rotational stiffness group to obtain an optimal preload force group, and summarizing the optimal preload force groups to obtain an optimal preload force group set;

[0074] An optimal preload force table is drawn according to the optimal preload force group set, wherein one optimal preload force in the optimal preload force table corresponds to one candidate variable temperature group and one candidate rotational stiffness group.

[0075] To achieve the above object, the present invention also provides an optimal preload force analysis system for an electric spindle, comprising:

[0076] An electric spindle stiffness test module is used to receive a preload force analysis instruction, set an initial spindle speed based on the preload force analysis instruction, start a pre-built electric spindle to be tested based on the initial spindle speed, obtain a running electric spindle, wherein the speed of the running electric spindle is the initial spindle speed, perform rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle, perform a rotational stiffness test on the balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and measure a spindle change temperature set of the balanced electric spindle based on the real-time measurement time set;

[0077] An acoustic wave preload force measurement module is used to start a pre-built preload force measurement unit, wherein the preload force measurement unit includes: an acoustic wave measurement unit and a piezoelectric measurement unit, and the acoustic wave measurement unit is an ultrasonic probe, and the piezoelectric measurement unit is a piezoelectric sensor, and the acoustic wave measurement unit is used to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set, wherein the acoustic wave measurement unit is arranged on both sides of the balanced electric spindle;

[0078] A preload force curve fitting module is used to perform piezoelectric measurement of the preload force of the balanced electric spindle using a piezoelectric measurement unit to obtain a piezoelectric preload force set, wherein the piezoelectric measurement unit is placed at the connection between the bearing and the spindle of the balanced electric spindle, and the preload force curves of the acoustic wave preload force set and the piezoelectric preload force set are respectively fitted according to the real-time measurement time set to obtain an acoustic wave preload force curve and a piezoelectric preload force curve;

[0079] A preload table construction module is used to identify candidate preload line segment sets based on the acoustic preload curve and the piezoelectric preload curve, and to confirm candidate test environment groups in the spindle rotation stiffness set and the spindle change temperature set respectively, wherein the candidate test environment groups include: candidate change temperature groups and candidate rotation stiffness groups, and to construct an optimal preload table based on the candidate preload line segment sets and the candidate test environment groups.

[0080] In order to solve the above problem, the present invention further provides an electronic device, the electronic device comprising:

[0081] a memory storing at least one instruction; and

[0082] The processor executes the instructions stored in the memory to implement the above-mentioned optimal preload force analysis method for the electric spindle.

[0083] In order to solve the above problem, the present invention also provides a computer-readable storage medium, in which at least one instruction is stored. The at least one instruction is executed by a processor in an electronic device to implement the above-mentioned optimal preload force analysis method for an electric spindle.

[0084] In order to solve the problems described in the background technology, the present invention first receives a preload analysis instruction, sets an initial spindle speed based on the preload analysis instruction, and starts the electric spindle to be tested based on the initial spindle speed to obtain a running electric spindle. The setting of the initial spindle speed ensures that the electric spindle is started under controllable conditions. Then, rotational vibration balancing is performed on the running electric spindle to obtain a balanced electric spindle. Through the balancing operation, the stability of the electric spindle during operation is ensured, the error caused by imbalance is reduced, and the accuracy of the best preload analysis of the electric spindle is improved. Then, a rotational stiffness test is performed on the balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and the spindle change temperature set of the balanced electric spindle is measured based on the real-time measurement time set. The determination of the spindle rotational stiffness set and the spindle change temperature set provides an environmental reference for the subsequent best preload analysis. The preload measurement unit is started, and the preload measurement unit is used to measure the preload of the balanced electric spindle to obtain an acoustic wave preload set and a piezoelectric preload set. This step is performed by two different methods: indirect measurement of acoustic waves and direct measurement of piezoelectric sensors. The preload force measurement of the balanced electric spindle is completed. The results obtained by these two methods can be verified with each other, which improves the accuracy of the preload force measurement, and thus improves the accuracy of the optimal preload force analysis of the electric spindle. According to the real-time measurement time set, the preload force curves of the acoustic wave preload force set and the piezoelectric preload force set are respectively fitted to obtain the acoustic wave preload force curve and the piezoelectric preload force curve. The curve fitting makes the obtained preload force data have an intuitive expression. Furthermore, according to the acoustic wave preload force curve and the piezoelectric preload force curve, the candidate preload force line segment set is identified. The candidate test environment groups are respectively confirmed in the spindle rotation stiffness set and the spindle change temperature set. This step completes the acquisition of the environmental parameters corresponding to the preload line segment set, providing the basic conditions for the subsequent optimal preload table. Finally, based on the candidate preload line segment set and the candidate test environment group set, the optimal preload table is constructed, and the optimal preload analysis of the electric spindle is completed based on the optimal preload table. The optimal preload table can be used to quickly confirm the optimal preload according to the actual temperature and stiffness, thereby improving the efficiency of the optimal preload analysis of the electric spindle. Therefore, the present invention can improve the accuracy and efficiency of the optimal preload analysis of the electric spindle. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1 A schematic flow chart of an optimal preload force analysis method for an electric spindle provided in one embodiment of the present invention;

[0086] Figure 2 A functional module diagram of an optimal preload force analysis system for an electric spindle provided by an embodiment of the present invention;

[0087] Figure 3 A schematic structural diagram of an electronic device for implementing the optimal preload force analysis method for an electric spindle provided in one embodiment of the present invention.

[0088] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0089] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0090] The embodiment of the present application provides an optimal preload analysis method for an electric spindle. The execution subject of the optimal preload analysis method for an electric spindle includes but is not limited to at least one of the electronic devices such as a server and a terminal that can be configured to execute the method provided in the embodiment of the present application. In other words, the optimal preload analysis method for an electric spindle can be executed by software or hardware installed on a terminal device or a server device, and the software can be a blockchain platform. The server includes but is not limited to: a single server, a server cluster, a cloud server or a cloud server cluster, etc.

[0091] Reference Figure 1 FIG. 1 is a flow chart of an optimal preload force analysis method for an electric spindle provided by an embodiment of the present invention. In this embodiment, the optimal preload force analysis method for an electric spindle includes:

[0092] S1. Receive a preload force analysis instruction, set an initial spindle speed based on the preload force analysis instruction, start a pre-built electric spindle to be tested based on the initial spindle speed, and obtain a running electric spindle, wherein the speed of the running electric spindle is the initial spindle speed.

[0093] It is understandable that the preload force analysis instruction refers to an instruction initiated manually to perform preload force analysis on the electric spindle to be tested, and the initial spindle speed is the speed of the electric spindle to be tested that is set manually. The initial spindle speed should be a smaller number at the beginning of setting to prevent the speed of the electric spindle to be tested from being too fast, which will cause greater difficulty in subsequent rotational balancing of the electric spindle. The electric spindle to be tested refers to the electric spindle that needs to be analyzed for preload force. The electric spindle to be tested mainly includes a spindle, a bearing and a rotor. The running electric spindle is the electric spindle to be tested that runs based on the initial spindle speed.

[0094] For example, Xiao Zhang is a staff member of a motor system. One day, Xiao Zhang needs to perform an optimal preload force analysis on an electric spindle to be tested in a power system. So Xiao Zhang sends a preload force analysis instruction to the power system through the motor control software. When the power system receives the preload force analysis instruction, it starts the electric spindle to be tested according to the preset initial spindle speed. After the startup is completed and the electric spindle to be tested runs at the initial spindle speed, it is the running electric spindle.

[0095] S2. Perform rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle.

[0096] It is clear that the balanced electric spindle refers to a running electric spindle that has been rotationally balanced. Since the electric spindle needs to be loaded in the subsequent test of the electric spindle's rotational stiffness, in order to avoid the added load from excessively changing the running state of the electric spindle, thereby causing excessive vibration of the electric spindle and thus damaging the electric spindle, it is necessary to perform vibration balancing on the running electric spindle in advance, and also to eliminate the influence of the current initial vibration of the electric spindle on the subsequent test results.

[0097] In detail, performing rotational vibration balancing on a running electric spindle to obtain a balanced electric spindle includes:

[0098] Performing area division in the running electric spindle to obtain a set of areas to be balanced, extracting the areas to be balanced in the set of areas to be balanced in turn and setting the balancing accuracy level, wherein each area to be balanced in the set of areas to be balanced has a displacement sensor;

[0099] Measuring the regional offset mass and the regional rotation radius of the area to be balanced, wherein the regional rotation radius is the distance between the center point of the area to be balanced and the rotation center of the rotor in the running electric spindle, calculating the regional balance amount and the regional controllable balance amount of the area to be balanced according to the regional offset mass and the regional rotation radius, and judging whether the regional balance amount is less than the regional controllable balance amount;

[0100] If the area to be balanced amount is not less than the area controllable balance amount, the vibration displacement component of the displacement sensor is obtained, wherein the vibration displacement component includes: radial vibration displacement and vertical vibration displacement, and the azimuth angle to be balanced is determined according to the vibration displacement component, wherein the azimuth angle to be balanced is expressed as:

[0101] ;

[0102] in, represents the azimuth to be balanced, represents the inverse tangent function, represents the vertical vibration displacement, Indicates radial vibration displacement, reduces the load of the area to be balanced according to the azimuth angle to be balanced and the preset unit load mass, obtains an adjusted balancing area, updates the area to be balanced using the adjusted balancing area, and returns to the step of measuring the area offset mass and the area rotation radius of the area to be balanced;

[0103] If the area to be balanced amount is less than the area controllable balance amount, the area to be balanced is recorded as a balance area, the balance areas are summarized to obtain a balance area set, and the running electric spindle is updated using the balance area set to obtain a balanced electric spindle.

[0104] It is understandable that the displacement sensor refers to a sensor that detects the change in the position of an object, which can convert the displacement of the object into an electrical signal. The displacement sensor is, for example, an inductive displacement sensor, which is installed near the bearing of the electric spindle. The balancing accuracy level refers to an artificially set constant. The balancing accuracy level is used to indicate the degree to which the area to be balanced currently needs to be balanced. It can be selected according to the needs of the actual situation. The area offset mass refers to the mass of the area to be balanced in the operating state. The area to be balanced amount refers to a numerical value used to indicate the current degree of mass offset of the area to be balanced. The area controllable balance amount refers to the minimum area to be balanced amount at which the area to be balanced can be balanced without vibration.

[0105] It can be understood that the vibration displacement component refers to the displacement vector measured by the displacement sensor, wherein the displacement sensor installed in the area to be balanced can measure the displacement vibration in the radial and vertical directions, wherein the radial direction is the direction of the line connecting the center of the area to be balanced and the rotation center of the running electric spindle rotor, and the vertical direction is the perpendicular direction to the radial direction, and the radial vibration displacement and the vertical vibration displacement refer to the displacement of the area to be balanced in the radial direction and the vertical direction, respectively. The azimuth to be balanced refers to the azimuth in which the load balance of the area to be balanced is required, and the azimuth to be balanced will be 0 degrees in the radial direction and 90 degrees in the vertical direction, and the unit load mass refers to the one-time reduction of the load mass set by humans, and the setting of the unit load mass is to prevent over-balancing caused by a large one-time reduction of the load mass.

[0106] In detail, the calculating of the regional balance amount and the regional controllable balance amount of the region to be balanced according to the regional offset mass and the regional rotation radius includes:

[0107] According to the regional offset mass and the regional rotation radius, the regional balance amount is calculated, wherein the regional balance amount is expressed as:

[0108] ;

[0109] in, Indicates the area to be balanced. represents the quality of regional migration, Indicates the area rotation radius;

[0110] The static area quality of the area to be balanced is obtained, and the regional controllable balancing amount of the area to be balanced is set according to the initial spindle speed, the regional rotation radius, the balancing accuracy level and the static area quality using the following formula:

[0111] ;

[0112] in, represents the controllable balance of the area, represents the static area quality, Indicates the balancing accuracy level, represents pi, Indicates the initial spindle speed.

[0113] It can be understood that the static area mass refers to the mass of the area to be balanced in a static state.

[0114] S3. Perform a rotational stiffness test on the balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and measure a spindle temperature change set of the balanced electric spindle based on the real-time measurement time set.

[0115] It can be understood that the spindle rotation stiffness refers to a value used to indicate the ability of the bearings in a balanced electric spindle to support the rotor under high-speed rotation. The spindle rotation stiffness can indicate the ability of the bearings in the electric spindle to resist deformation under high-speed operation. The real-time measurement time refers to the time when the stiffness of the balanced electric spindle is measured. The spindle variable temperature refers to the temperature of the rotor in the electric spindle during operation. It is measured using a temperature sensor, and the time of temperature measurement should be consistent with the time of stiffness measurement, that is, the measurement time of the spindle variable temperature set is the real-time measurement time set.

[0116] In detail, the rotational stiffness test of the balanced electric spindle is performed to obtain a spindle rotational stiffness set and a real-time measurement time set, including:

[0117] Using the multiple displacement sensors to measure the initial vibration displacement set of the balanced electric spindle, and recording the current initial load mass and the real-time measurement time, wherein the number of initial vibration displacements in the initial vibration displacement set is the same as the number of displacement sensors in the multiple displacement sensors;

[0118] According to the unit load mass, the initial load mass of the balanced electric spindle is increased to obtain a loaded electric spindle, wherein the position where the load mass is increased is a load device connected to the balanced electric spindle;

[0119] Acquire the current load speed of the loaded electric spindle, increase the speed of the current load speed, and when the current load speed is equal to the initial spindle speed, stop increasing the speed of the current load speed and measure the vibration displacement of the loaded electric spindle to obtain a target vibration displacement set;

[0120] Acquire the current running load mass, and identify the maximum initial displacement and the maximum target displacement in the initial vibration displacement set and the target vibration displacement set, respectively, wherein the maximum initial displacement and the maximum target displacement are both vector synthetic displacements;

[0121] Calculating the spindle rotation stiffness according to the maximum initial displacement, the maximum target displacement and the running load mass;

[0122] Using the load electric spindle and the running load mass to update the balanced electric spindle and the initial load mass respectively, and returning to the step of increasing the load mass of the initial load mass of the balanced electric spindle according to the unit load mass, until the spindle rotation stiffness quantity obtained is not less than the preset reference stiffness quantity;

[0123] The spindle rotation stiffness and the real-time measurement time are respectively summarized to obtain a spindle rotation stiffness set and a real-time measurement time set.

[0124] It can be understood that the initial vibration displacement set refers to the vibration displacement of the balanced electric spindle before the stiffness test is performed on the balanced electric spindle, the initial load mass refers to the load mass carried by the balanced electric spindle before the stiffness test is performed on the balanced electric spindle, the loaded electric spindle refers to the balanced electric spindle after the unit load mass is increased, and the current load speed refers to the current speed of the loaded electric spindle. After the load is added to the balanced electric spindle, the speed of the balanced electric spindle will decrease, that is, the current load speed will be lower than the initial spindle speed. In order to ensure the controllability of subsequent variables, the current load speed needs to be increased to the initial spindle speed.

[0125] It should be explained that the target vibration displacement set refers to the vibration displacement of the load electric spindle at the initial spindle speed, the operating load mass refers to the total load mass currently borne by the load electric spindle, the maximum initial displacement and the maximum target displacement refer to the maximum initial vibration displacement and the maximum target vibration displacement in the initial vibration displacement set and the target vibration displacement set respectively, and the maximum initial displacement and the maximum target displacement are both vector synthetic displacements.

[0126] In detail, the calculation of the spindle rotation stiffness according to the maximum initial displacement, the maximum target displacement and the running load mass includes:

[0127] Identify the maximum difference angle between the maximum initial displacement and the maximum target displacement, and calculate the spindle rotation stiffness according to the initial spindle speed, the maximum difference angle, the running load mass, the maximum initial displacement and the maximum target displacement, wherein the spindle rotation stiffness is expressed as:

[0128] ;

[0129] in, represents the spindle rotation stiffness, Indicates the running load mass, represents the maximum initial displacement, represents the maximum target displacement, represents the absolute value symbol, represents the cosine function, Indicates the maximum difference angle.

[0130] It can be understood that the maximum difference angle refers to the vector angle between the maximum initial displacement and the maximum target displacement.

[0131] S4. Start a pre-built preload force measurement unit, wherein the preload force measurement unit includes: an acoustic wave measurement unit and a piezoelectric measurement unit, and the acoustic wave measurement unit is an ultrasonic probe, and the piezoelectric measurement unit is a piezoelectric sensor.

[0132] It can be understood that the preload force measuring unit refers to a device for measuring the preload force of the balanced electric spindle, and the preload force measuring unit includes an acoustic wave measuring unit and a voltage measuring unit, wherein the acoustic wave measuring unit is an ultrasonic probe, and the ultrasonic probe is installed on both sides of the balanced electric spindle. The acoustic wave preload force of the balanced electric spindle can be measured by emitting and receiving acoustic waves to and from the balanced electric spindle through the ultrasonic probe, and the piezoelectric measuring unit is composed of a plurality of piezoelectric sensors, and a plurality of voltage sensors are dispersedly installed on the side surface of the balanced electric spindle.

[0133] S5. Performing acoustic wave measurement of the preload force of the balanced electric spindle by using an acoustic wave measurement unit to obtain an acoustic wave preload force set, wherein the acoustic wave measurement unit is arranged on both sides of the balanced electric spindle.

[0134] It can be understood that the acoustic wave preload refers to the pressure borne by the bearings in the balanced electric spindle, and the acoustic wave preload is measured by an ultrasonic probe.

[0135] In detail, the method of using an acoustic wave measurement unit to perform acoustic wave measurement on the preload force of the balanced electric spindle to obtain an acoustic wave preload force set includes:

[0136] Acquiring the acoustic-elastic coefficient of the acoustic-wave measurement unit, wherein the acoustic-elastic coefficient includes: the acoustic-elastic coefficient of a transverse wave and the acoustic-elastic coefficient of a longitudinal wave;

[0137] Confirming an effective rotational position in the balanced electric spindle, identifying the total spindle length of the balanced electric spindle and the effective rotational length of the effective rotational position, respectively, and obtaining a measurement contact area between the acoustic wave measurement unit and the balanced electric spindle;

[0138] The following operations are performed for each real-time measurement moment in the real-time measurement moment set:

[0139] Based on the real-time measurement moment, the acoustic wave measuring unit is used to perform acoustic wave monitoring on the balanced electric spindle, wherein the acoustic wave monitoring process is that the acoustic wave measuring unit emits ultrasonic waves to the balanced electric spindle and records the propagation speed of the ultrasonic waves when propagating in the balanced electric spindle;

[0140] Recording the sound wave propagation speed of the ultrasonic wave when it propagates in the balanced electric spindle during the sound wave monitoring process, wherein the sound wave propagation speed includes: longitudinal wave propagation speed and shear wave propagation speed;

[0141] According to the acoustic wave propagation velocity, acoustic wave acoustoelastic coefficient, effective rotation length, total spindle length and measured contact area, the acoustic wave preload force is calculated using the following formula:

[0142] ;

[0143] in, Indicates the acoustic preload force, represents the total length of the main axis, represents the shear wave propagation speed, Represents the measured contact area, represents the effective rotation length, represents the shear wave acoustoelastic coefficient, represents the longitudinal wave acoustoelastic coefficient, represents the propagation speed of longitudinal waves;

[0144] The acoustic wave preload forces are aggregated to obtain an acoustic wave preload force set.

[0145] It is clear that the acoustic wave acoustoelastic coefficient refers to the physical quantity of the change in the speed of sound of a material when it is subjected to stress, which includes the transverse wave acoustoelastic coefficient and the longitudinal wave acoustoelastic coefficient. The transverse wave acoustoelastic coefficient and the longitudinal wave acoustoelastic coefficient can be obtained by consulting relevant literature or performing preliminary experiments on the balanced electric spindle. The effective rotating part refers to the part of the balanced electric spindle that actually participates in the rotation work. Since there is a connection part connecting the balanced electric spindle and the related load in the balanced electric spindle, the effective rotating part is removed from the balanced electric spindle. The total length of the spindle refers to the total length of the balanced electric spindle, the effective rotating length refers to the total length of the effective rotating part, the measuring contact area refers to the total contact area between the acoustic wave measuring unit and the balanced electric spindle, and the longitudinal wave propagation speed and the transverse wave propagation speed are the speeds at which the longitudinal wave and the transverse wave propagate in the balanced electric spindle, respectively.

[0146] S6. Perform piezoelectric measurement of the preload force of the balanced electric spindle using a piezoelectric measurement unit to obtain a piezoelectric preload force set, wherein the piezoelectric measurement unit is placed at the connection between the bearing and the spindle of the balanced electric spindle.

[0147] It can be understood that the piezoelectric preload refers to the pressure borne by the bearings in the balanced electric spindle. The piezoelectric preload has the same physical meaning as the acoustic preload, but the piezoelectric preload and the acoustic preload are measured differently. The piezoelectric preload is measured by a piezoelectric sensor.

[0148] It needs to be explained that the piezoelectric sensor can directly measure the pressure on the bearings in the balanced electric spindle, and use the pressure as the piezoelectric preload. The ultrasonic probe indirectly measures the acoustic wave preload based on the speed at which ultrasonic waves propagate in the balanced electric spindle. The acoustic wave preload and the piezoelectric preload are verified with each other to ensure that the error between the measured preload and the actual preload is small, thereby improving the accuracy of the entire optimal preload analysis.

[0149] In detail, the piezoelectric measurement unit is used to perform piezoelectric measurement on the preload force of the balanced electric spindle to obtain a piezoelectric preload force set, including:

[0150] Identifying a plurality of piezoelectric sensors of the piezoelectric measuring unit, wherein the number of the piezoelectric sensors is manually set, and the plurality of piezoelectric sensors are evenly mounted on the side surface of the bearing in the balancing electric spindle;

[0151] The following operations are performed for each real-time measurement moment in the real-time measurement moment set:

[0152] Starting the piezoelectric measuring unit and using the piezoelectric measuring unit to measure the pressure of the balancing electric spindle to obtain an original measured pressure set, wherein the number of original measured pressures in the original measured pressure set is the same as the number of piezoelectric sensors in the piezoelectric measuring unit;

[0153] Identifying a first maximum pressure and a second maximum pressure in the original measured pressure set, and identifying a first measurement position and a second measurement position corresponding to the first maximum pressure and the second maximum pressure, respectively;

[0154] Calculating the piezoelectric azimuth angles at the first measurement position and the second measurement position, and determining whether the piezoelectric azimuth angle is less than a preset standard azimuth angle;

[0155] If the piezoelectric azimuth angle is not less than the standard azimuth angle, the piezoelectric preload force is calculated according to the first maximum pressure, the second maximum pressure and the piezoelectric azimuth angle, wherein the piezoelectric preload force is expressed as:

[0156] ;

[0157] in, represents the piezoelectric preload, Indicates the first extreme pressure, Indicates the second greatest pressure, represents the piezoelectric azimuth;

[0158] If the piezoelectric azimuth angle is smaller than the standard azimuth angle, the first maximum pressure is recorded as the piezoelectric preload force;

[0159] The piezoelectric preload forces are aggregated to obtain a piezoelectric preload force set.

[0160] It can be understood that the original measured pressure refers to the pressure value measured by the piezoelectric sensor in the piezoelectric measuring unit, the first maximum pressure refers to the original measured pressure with the largest value in the original measured pressure concentration, the second maximum pressure refers to the original measured pressure with the second largest value in the original measured pressure concentration, the first measurement position indicator is the position of the piezoelectric sensor of the first maximum pressure, the second measurement position indicator is the position of the piezoelectric sensor of the second maximum pressure, the piezoelectric azimuth refers to the angle between the first measurement position and the second measurement position, and the standard azimuth refers to an artificially set piezoelectric azimuth.

[0161] It needs to be explained that since the direction of the pressure on the bearing in the running electric spindle is not fixed, the pressures measured by different piezoelectric sensors in the piezoelectric measuring unit at the same time are all different. Among them, the pressure with the largest reading can be regarded as the main pressure, that is, the piezoelectric preload. However, due to the limitation of the number of piezoelectric sensors, it is impossible to accurately measure the direction of the pressure on the bearing. Therefore, there will be a certain deviation if only the first maximum pressure is used as the piezoelectric preload. Therefore, the second maximum pressure is introduced. When the position of the second maximum pressure is very close to the first maximum pressure, that is, the piezoelectric azimuth is less than the standard azimuth, it can be considered that the pressure direction measured by the first maximum pressure at this time is close to the actual direction, and the first maximum pressure can be regarded as the piezoelectric preload. When the piezoelectric azimuth is not less than the standard azimuth, it means that there is a certain deviation between the actual pressure direction and the first maximum pressure at this time. At this time, the piezoelectric preload needs to be comprehensively calculated based on the first maximum pressure and the second maximum pressure.

[0162] S7. According to the real-time measurement time set, preload force curve fitting is performed on the acoustic wave preload force set and the piezoelectric preload force set respectively to obtain an acoustic wave preload force curve and a piezoelectric preload force curve.

[0163] It can be understood that since the measurements of the acoustic wave preload and the piezoelectric preload are both carried out at the real-time measurement time, the acoustic wave preload set and the piezoelectric preload set are both time series sets sorted according to the real-time measurement time. Therefore, the acoustic wave preload set and the piezoelectric preload set can be curve fitted according to the real-time measurement time set to obtain the acoustic wave preload curve and the piezoelectric preload curve, wherein the horizontal coordinate of the acoustic wave preload curve is the real-time measurement time, and the vertical coordinate is the acoustic wave preload, and the horizontal coordinate of the piezoelectric preload curve is the real-time measurement time, and the vertical coordinate is the piezoelectric preload.

[0164] S8. According to the acoustic preload curve and the piezoelectric preload curve, identify the candidate preload line segment set and confirm the candidate test environment group set in the spindle rotation stiffness set and the spindle change temperature set respectively, wherein the candidate test environment group set includes: a candidate change temperature group set and a candidate rotation stiffness group set.

[0165] It can be understood that the candidate preload line segment set refers to the set of lines obtained after mutual verification of the acoustic preload curve and the piezoelectric preload curve, the candidate change temperature group refers to the combination of the spindle change temperature when the preload force of the balanced electric spindle is the preload force on the candidate preload line segment, and the candidate rotational stiffness group refers to the combination of the spindle rotational stiffness when the preload force of the balanced electric spindle is the preload force on the candidate preload line segment.

[0166] In detail, the identifying of the candidate preload line segment set and confirming the candidate test environment group set in the spindle rotation stiffness set and the spindle temperature change set respectively include:

[0167] Performing line segment division on the acoustic wave preload force curve to obtain an acoustic wave line segment set, and identifying an acoustic wave preload force coefficient set and an acoustic wave time period set of the acoustic wave line segment set, wherein the acoustic wave preload force coefficient is the slope of the acoustic wave line segment, and the acoustic wave time period is the horizontal coordinate range of the acoustic wave line segment;

[0168] Dividing the piezoelectric preload force curve into segments according to the acoustic wave time period set to obtain a piezoelectric line segment set, and identifying a piezoelectric preload force coefficient set of the piezoelectric line segment set;

[0169] Extracting the acoustic wave preload coefficient and the piezoelectric preload coefficient from the acoustic wave preload coefficient set and the piezoelectric preload coefficient set respectively, and calculating the coefficient difference between the acoustic wave preload coefficient and the piezoelectric preload coefficient;

[0170] Determine whether the coefficient difference is less than a preset standard deviation;

[0171] If the coefficient difference is less than the standard deviation, respectively identifying candidate acoustic wave segments and candidate piezoelectric line segments of the acoustic wave preload coefficient and the piezoelectric preload coefficient, averaging the candidate acoustic wave segments and candidate piezoelectric line segments to obtain candidate preload line segments;

[0172] Identify candidate acoustic wave time periods of candidate preload force line segments in the acoustic wave time period set, and confirm candidate temperature change groups and candidate rotational stiffness groups in the spindle temperature change set and spindle rotational stiffness set based on the candidate acoustic wave time periods;

[0173] The candidate preload line segments, candidate change temperature groups and candidate rotational stiffness groups are respectively summarized to obtain a candidate preload line segment set, a candidate change temperature group set and a candidate rotational stiffness group set.

[0174] It can be understood that the acoustic wave segment set refers to the acoustic wave preload force curve after segment division, wherein the division method is artificial division or division according to a pre-set division program, for example: the acoustic wave preload force curve is divided into 10 equal parts, the acoustic wave preload force coefficient refers to the overall slope of the acoustic wave segment, and its calculation method is to calculate the slope between the starting point and the end point of the acoustic wave segment, the acoustic wave time period refers to the range of the real-time measurement time of the acoustic wave preload force on the acoustic wave segment, the piezoelectric line segment refers to the piezoelectric preload force curve after segment division, and the piezoelectric preload force coefficient refers to the line segment coefficient of the piezoelectric line segment, and its calculation method is the same as the calculation method of the acoustic wave preload force coefficient.

[0175] It can be understood that the coefficient difference refers to the difference between the acoustic wave preload coefficient and the piezoelectric preload coefficient, the candidate acoustic wave segment refers to the acoustic wave segment corresponding to the acoustic wave preload coefficient, the candidate piezoelectric line segment refers to the piezoelectric line segment corresponding to the piezoelectric preload coefficient, and the candidate preload force segment refers to the line segment after averaging the candidate acoustic wave segment and the candidate piezoelectric line segment, wherein averaging refers to superimposing the candidate acoustic wave segment and the candidate piezoelectric line segment on the vertical axis and dividing by 2, and the line segment obtained in this way is the candidate preload force segment, and the candidate acoustic wave time period is the range of real-time measurement time corresponding to the horizontal coordinate in the candidate preload force segment, and further, the candidate change temperature group can also refer to the combination of spindle change temperatures corresponding to the candidate acoustic wave time period, and the candidate rotational stiffness group can also refer to the combination of spindle rotational stiffnesses corresponding to the candidate acoustic wave time period.

[0176] S9. Based on the candidate preload line segment set and the candidate test environment group set, an optimal preload table is constructed, and based on the optimal preload table, an optimal preload analysis of the electric spindle is completed.

[0177] In detail, the constructing of the optimal preload table based on the candidate preload line segment set and the candidate test environment group set includes:

[0178] Extracting candidate preload line segments, candidate change temperature groups and candidate rotational stiffness groups in sequence from the candidate preload line segment set, candidate change temperature group set and candidate rotational stiffness group set respectively;

[0179] Identifying the minimum change temperature and the maximum rotational stiffness in the candidate change temperature group and the candidate rotational stiffness group, respectively, and identifying the minimum temperature moment and the maximum stiffness moment of the minimum change temperature and the maximum rotational stiffness, respectively;

[0180] Based on the minimum temperature moment and the maximum stiffness moment, confirming the temperature mapping preload and the stiffness mapping preload in the candidate preload line segment, calculating the median preload of the temperature mapping preload and the stiffness mapping preload, and recording the median preload as the optimal preload;

[0181] Key-pairing the optimal preload force, the candidate temperature change group and the candidate rotational stiffness group to obtain an optimal preload force group, and summarizing the optimal preload force groups to obtain an optimal preload force group set;

[0182] An optimal preload force table is drawn according to the optimal preload force group set, wherein one optimal preload force in the optimal preload force table corresponds to one candidate variable temperature group and one candidate rotational stiffness group.

[0183] It can be understood that the minimum change temperature refers to the candidate change temperature with the smallest value in the candidate change temperature group, the maximum rotational stiffness refers to the candidate rotational stiffness with the largest value in the candidate rotational stiffness group, the minimum temperature moment refers to the real-time measurement moment corresponding to the minimum change temperature, the maximum stiffness moment refers to the real-time measurement moment corresponding to the maximum rotational stiffness, the temperature mapping preload and the stiffness mapping preload respectively refer to the preloads in the candidate preload line segment with the horizontal axes being the minimum temperature moment and the maximum stiffness moment, and the median preload refers to the average value of the temperature mapping preload and the stiffness mapping preload.

[0184] For example, Xiao Wang is a staff member of an electric power system. Once, Xiao Wang wants to adjust the preload force of an electric spindle, so Xiao Wang obtains the temperature a and stiffness b of the electric spindle at this time, and searches in the optimal preload force table based on the temperature a and stiffness b, and obtains that the optimal preload force under the conditions of temperature a and stiffness b is c, so Xiao Wang adjusts the preload force of the electric spindle to c.

[0185] In order to solve the problems described in the background technology, the present invention first receives a preload analysis instruction, sets an initial spindle speed based on the preload analysis instruction, and starts the electric spindle to be tested based on the initial spindle speed to obtain a running electric spindle. The setting of the initial spindle speed ensures that the electric spindle is started under controllable conditions. Then, rotational vibration balancing is performed on the running electric spindle to obtain a balanced electric spindle. Through the balancing operation, the stability of the electric spindle during operation is ensured, the error caused by imbalance is reduced, and the accuracy of the best preload analysis of the electric spindle is improved. Then, a rotational stiffness test is performed on the balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and the spindle change temperature set of the balanced electric spindle is measured based on the real-time measurement time set. The determination of the spindle rotational stiffness set and the spindle change temperature set provides an environmental reference for the subsequent best preload analysis. The preload measurement unit is started, and the preload measurement unit is used to measure the preload of the balanced electric spindle to obtain an acoustic wave preload set and a piezoelectric preload set. This step is performed by two different methods: indirect measurement of acoustic waves and direct measurement of piezoelectric sensors. The preload force measurement of the balanced electric spindle is completed. The results obtained by these two methods can be verified with each other, which improves the accuracy of the preload force measurement, and thus improves the accuracy of the optimal preload force analysis of the electric spindle. According to the real-time measurement time set, the preload force curves of the acoustic wave preload force set and the piezoelectric preload force set are respectively fitted to obtain the acoustic wave preload force curve and the piezoelectric preload force curve. The curve fitting makes the obtained preload force data have an intuitive expression. Furthermore, according to the acoustic wave preload force curve and the piezoelectric preload force curve, the candidate preload force line segment set is identified. The candidate test environment groups are respectively confirmed in the spindle rotation stiffness set and the spindle change temperature set. This step completes the acquisition of the environmental parameters corresponding to the preload line segment set, providing the basic conditions for the subsequent optimal preload table. Finally, based on the candidate preload line segment set and the candidate test environment group set, the optimal preload table is constructed, and the optimal preload analysis of the electric spindle is completed based on the optimal preload table. The optimal preload table can be used to quickly confirm the optimal preload according to the actual temperature and stiffness, thereby improving the efficiency of the optimal preload analysis of the electric spindle. Therefore, the present invention can improve the accuracy and efficiency of the optimal preload analysis of the electric spindle.

[0186] like Figure 2 1 is a functional module diagram of an optimal preload force analysis system for an electric spindle provided in one embodiment of the present invention.

[0187] The optimal preload force analysis system 100 for an electric spindle of the present invention can be installed in an electronic device. According to the functions to be implemented, the optimal preload force analysis system 100 for an electric spindle can include an electric spindle stiffness test module 101, an acoustic preload force measurement module 102, a preload force curve fitting module 103, and a preload force table construction module 104. The module of the present invention can also be referred to as a unit, which refers to a series of computer program segments that can be executed by an electronic device processor and can complete fixed functions, which are stored in the memory of the electronic device.

[0188] The electric spindle stiffness test module 101 is used to receive a preload force analysis instruction, set an initial spindle speed based on the preload force analysis instruction, start a pre-built electric spindle to be tested based on the initial spindle speed, and obtain a running electric spindle, wherein the speed of the running electric spindle is the initial spindle speed, perform rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle, perform a rotational stiffness test on the balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and measure a spindle change temperature set of the balanced electric spindle based on the real-time measurement time set;

[0189] The acoustic wave preload force measurement module 102 is used to start a pre-built preload force measurement unit, wherein the preload force measurement unit includes: an acoustic wave measurement unit and a piezoelectric measurement unit, and the acoustic wave measurement unit is an ultrasonic probe, and the piezoelectric measurement unit is a piezoelectric sensor, and the acoustic wave measurement unit is used to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set, wherein the acoustic wave measurement unit is arranged on both sides of the balanced electric spindle;

[0190] The preload force curve fitting module 103 is used to perform piezoelectric measurement of the preload force of the balanced electric spindle using a piezoelectric measurement unit to obtain a piezoelectric preload force set, wherein the piezoelectric measurement unit is placed at the connection between the bearing and the spindle of the balanced electric spindle, and the preload force curves of the acoustic wave preload force set and the piezoelectric preload force set are respectively fitted according to the real-time measurement time set to obtain an acoustic wave preload force curve and a piezoelectric preload force curve;

[0191] The preload table construction module 104 is used to identify candidate preload line segment sets based on the acoustic preload curve and the piezoelectric preload curve and to confirm candidate test environment groups in the spindle rotation stiffness set and the spindle change temperature set respectively, wherein the candidate test environment groups include: candidate change temperature groups and candidate rotation stiffness groups, and to construct an optimal preload table based on the candidate preload line segment sets and the candidate test environment groups.

[0192] In detail, the modules in the optimal preload force analysis system 100 for the electric spindle in the embodiment of the present invention are used in the same manner as described above. Figure 1The optimal preload force analysis method for the electric spindle described in the invention is the same technical means and can produce the same technical effect, so it will not be repeated here.

[0193] like Figure 3 FIG. 1 is a schematic diagram of the structure of an electronic device for implementing an optimal preload force analysis method for an electric spindle provided by an embodiment of the present invention.

[0194] The electronic device 1 may include a processor 10, a memory 11 and a bus 12, and may also include a computer program stored in the memory 11 and executable on the processor 10, such as an optimal preload force analysis method program for an electric spindle.

[0195] The memory 11 includes at least one type of readable storage medium, including flash memory, mobile hard disk, multimedia card, card-type memory (such as SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the memory 11 may be an internal storage unit of the electronic device 1, such as a mobile hard disk of the electronic device 1. In other embodiments, the memory 11 may also be an external storage device of the electronic device 1, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device 1. Further, the memory 11 also includes an internal storage unit of the electronic device 1 and an external storage device. The memory 11 can not only be used to store application software and various types of data installed in the electronic device 1, such as the code of the optimal preload analysis method program for the electric spindle, but also can be used to temporarily store data that has been output or is to be output.

[0196] The processor 10 may be composed of an integrated circuit in some embodiments, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and combinations of various control chips, etc. The processor 10 is the control core (Control Unit) of the electronic device, and uses various interfaces and lines to connect various components of the entire electronic device, and executes various functions and processes data of the electronic device 1 by running or executing programs or modules (such as the optimal preload analysis method program for the electric spindle, etc.) stored in the memory 11, and calling data stored in the memory 11.

[0197] The bus 12 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 12 may be divided into an address bus, a data bus, a control bus, etc. The bus 12 is configured to realize connection and communication between the memory 11 and at least one processor 10, etc.

[0198] Figure 3 Only an electronic device with components is shown, and those skilled in the art will understand that Figure 3 The structure shown does not constitute a limitation on the electronic device 1, and may include fewer or more components than shown in the figure, or combine certain components, or arrange the components differently.

[0199] For example, although not shown, the electronic device 1 may also include a power source (such as a battery) for supplying power to various components. Preferably, the power source may be logically connected to the at least one processor 10 through a power management system, so that the power management system can realize functions such as charging management, discharging management, and power consumption management. The power source may also include any components such as one or more DC or AC power sources, recharging systems, power failure detection circuits, power converters or inverters, and power status indicators. The electronic device 1 may also include a variety of sensors, Bluetooth modules, Wi-Fi modules, etc., which will not be repeated here.

[0200] Furthermore, the electronic device 1 may also include a network interface. Optionally, the network interface may include a wired interface and / or a wireless interface (such as a WI-FI interface, a Bluetooth interface, etc.), which is generally used to establish a communication connection between the electronic device 1 and other electronic devices.

[0201] Optionally, the electronic device 1 may further include a user interface, which may be a display, an input unit (such as a keyboard), or a standard wired interface or a wireless interface. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, and an OLED (Organic Light-Emitting Diode) touch device. The display may also be appropriately referred to as a display screen or a display unit, which is used to display information processed in the electronic device 1 and to display a visual user interface.

[0202] The optimal preload force analysis method program for the electric spindle stored in the memory 11 of the electronic device 1 is a combination of multiple instructions. When running in the processor 10, it can achieve:

[0203] Receiving a preload force analysis instruction, setting an initial spindle speed based on the preload force analysis instruction, starting a pre-built electric spindle to be tested based on the initial spindle speed, and obtaining a running electric spindle, wherein the speed of the running electric spindle is the initial spindle speed;

[0204] Performing rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle;

[0205] Performing a rotational stiffness test on a balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and measuring a spindle temperature change set of the balanced electric spindle based on the real-time measurement time set;

[0206] Starting a pre-built preload force measurement unit, wherein the preload force measurement unit includes: an acoustic wave measurement unit and a piezoelectric measurement unit, wherein the acoustic wave measurement unit is an ultrasonic probe, and the piezoelectric measurement unit is a piezoelectric sensor;

[0207] Using an acoustic wave measurement unit to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set, wherein the acoustic wave measurement unit is arranged on both sides of the balanced electric spindle;

[0208] Using a piezoelectric measuring unit to perform piezoelectric measurement of the preload force of the balancing electric spindle to obtain a piezoelectric preload force set, wherein the piezoelectric measuring unit is placed at the connection between the bearing and the spindle of the balancing electric spindle;

[0209] According to the real-time measurement time set, preload force curve fitting is performed on the acoustic wave preload force set and the piezoelectric preload force set respectively to obtain an acoustic wave preload force curve and a piezoelectric preload force curve;

[0210] According to the acoustic preload curve and the piezoelectric preload curve, a candidate preload line segment set is identified and a candidate test environment group set is respectively confirmed in the spindle rotation stiffness set and the spindle change temperature set, wherein the candidate test environment group set includes: a candidate change temperature group set and a candidate rotation stiffness group set;

[0211] Based on the candidate preload line segment set and the candidate test environment group set, an optimal preload table is constructed, and based on the optimal preload table, an optimal preload analysis of the electric spindle is completed.

[0212] Specifically, the specific implementation method of the processor 10 for the above instructions can refer to Figures 1 to 3 The description of the relevant steps in the corresponding embodiments will not be repeated here.

[0213] Furthermore, if the module / unit integrated in the electronic device 1 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. The computer-readable storage medium can be volatile or non-volatile. For example, the computer-readable medium can include: any entity or system that can carry the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0214] The present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor of an electronic device, the computer program can implement:

[0215] Receiving a preload force analysis instruction, setting an initial spindle speed based on the preload force analysis instruction, starting a pre-built electric spindle to be tested based on the initial spindle speed, and obtaining a running electric spindle, wherein the speed of the running electric spindle is the initial spindle speed;

[0216] Performing rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle;

[0217] Performing a rotational stiffness test on a balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and measuring a spindle temperature change set of the balanced electric spindle based on the real-time measurement time set;

[0218] Starting a pre-built preload force measurement unit, wherein the preload force measurement unit includes: an acoustic wave measurement unit and a piezoelectric measurement unit, wherein the acoustic wave measurement unit is an ultrasonic probe, and the piezoelectric measurement unit is a piezoelectric sensor;

[0219] Using an acoustic wave measurement unit to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set, wherein the acoustic wave measurement unit is arranged on both sides of the balanced electric spindle;

[0220] Using a piezoelectric measuring unit to perform piezoelectric measurement of the preload force of the balancing electric spindle to obtain a piezoelectric preload force set, wherein the piezoelectric measuring unit is placed at the connection between the bearing and the spindle of the balancing electric spindle;

[0221] According to the real-time measurement time set, preload force curve fitting is performed on the acoustic wave preload force set and the piezoelectric preload force set respectively to obtain an acoustic wave preload force curve and a piezoelectric preload force curve;

[0222] According to the acoustic preload curve and the piezoelectric preload curve, a candidate preload line segment set is identified and a candidate test environment group set is respectively confirmed in the spindle rotation stiffness set and the spindle change temperature set, wherein the candidate test environment group set includes: a candidate change temperature group set and a candidate rotation stiffness group set;

[0223] Based on the candidate preload line segment set and the candidate test environment group set, an optimal preload table is constructed, and based on the optimal preload table, an optimal preload analysis of the electric spindle is completed.

[0224] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, systems and methods can be implemented in other ways. For example, the system embodiments described above are only illustrative, and actual implementation may have other division methods.

[0225] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0226] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0227] It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0228] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. An optimal preload force analysis method for an electric spindle, characterized in that: The method comprises: Receiving a preload force analysis instruction, setting an initial spindle speed based on the preload force analysis instruction, starting a pre-built electric spindle to be tested based on the initial spindle speed, and obtaining a running electric spindle, wherein the speed of the running electric spindle is the initial spindle speed; Performing rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle; Performing a rotational stiffness test on a balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and measuring a spindle temperature change set of the balanced electric spindle based on the real-time measurement time set; Starting a pre-built preload force measurement unit, wherein the preload force measurement unit includes: an acoustic wave measurement unit and a piezoelectric measurement unit, wherein the acoustic wave measurement unit is an ultrasonic probe, and the piezoelectric measurement unit is a piezoelectric sensor; Using an acoustic wave measurement unit to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set, wherein the acoustic wave measurement unit is arranged on both sides of the balanced electric spindle; Using a piezoelectric measuring unit to perform piezoelectric measurement of the preload force of the balancing electric spindle to obtain a piezoelectric preload force set, wherein the piezoelectric measuring unit is placed at the connection between the bearing and the spindle of the balancing electric spindle; According to the real-time measurement time set, preload force curve fitting is performed on the acoustic wave preload force set and the piezoelectric preload force set respectively to obtain an acoustic wave preload force curve and a piezoelectric preload force curve; According to the acoustic preload curve and the piezoelectric preload curve, a candidate preload line segment set is identified and a candidate test environment group set is respectively confirmed in the spindle rotation stiffness set and the spindle change temperature set, wherein the candidate test environment group set includes: a candidate change temperature group set and a candidate rotation stiffness group set; Based on the candidate preload line segment set and the candidate test environment group set, an optimal preload table is constructed, and based on the optimal preload table, an optimal preload analysis of the electric spindle is completed.

2. The optimal preload force analysis method for an electric spindle according to claim 1, characterized in that: The method of performing rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle comprises: Performing area division in the running electric spindle to obtain a set of areas to be balanced, extracting the areas to be balanced in the set of areas to be balanced in turn and setting the balancing accuracy level, wherein each area to be balanced in the set of areas to be balanced has a displacement sensor; Measuring the regional offset mass and the regional rotation radius of the area to be balanced, wherein the regional rotation radius is the distance between the center point of the area to be balanced and the rotation center of the rotor in the running electric spindle, calculating the regional balance amount and the regional controllable balance amount of the area to be balanced according to the regional offset mass and the regional rotation radius, and judging whether the regional balance amount is less than the regional controllable balance amount; If the area to be balanced amount is not less than the area controllable balance amount, the vibration displacement component of the displacement sensor is obtained, wherein the vibration displacement component includes: radial vibration displacement and vertical vibration displacement, and the azimuth angle to be balanced is determined according to the vibration displacement component, wherein the azimuth angle to be balanced is expressed as: ； in, represents the azimuth to be balanced, represents the inverse tangent function, represents the vertical vibration displacement, Indicates radial vibration displacement, reduces the load of the area to be balanced according to the azimuth angle to be balanced and the preset unit load mass, obtains an adjusted balancing area, updates the area to be balanced using the adjusted balancing area, and returns to the step of measuring the area offset mass and the area rotation radius of the area to be balanced; If the area to be balanced amount is less than the area controllable balance amount, the area to be balanced is recorded as a balance area, the balance areas are summarized to obtain a balance area set, and the running electric spindle is updated using the balance area set to obtain a balanced electric spindle.

3. The optimal preload force analysis method for an electric spindle according to claim 2, characterized in that: The calculating, according to the regional offset mass and the regional rotation radius, the regional balance amount and the regional controllable balance amount of the region to be balanced includes: According to the regional offset mass and the regional rotation radius, the regional balance amount is calculated, wherein the regional balance amount is expressed as: ； in, Indicates the area to be balanced. represents the quality of regional migration, Indicates the area rotation radius; The static area quality of the area to be balanced is obtained, and the regional controllable balancing amount of the area to be balanced is set according to the initial spindle speed, the regional rotation radius, the balancing accuracy level and the static area quality using the following formula: ； in, represents the controllable balance of the area, represents the static area quality, Indicates the balancing accuracy level, represents pi, Indicates the initial spindle speed.

4. The optimal preload force analysis method for an electric spindle according to claim 3, characterized in that: The rotating stiffness test of the balanced electric spindle is performed to obtain a spindle rotating stiffness set and a real-time measurement time set, including: Using the multiple displacement sensors to measure the initial vibration displacement set of the balanced electric spindle, and recording the current initial load mass and the real-time measurement time, wherein the number of initial vibration displacements in the initial vibration displacement set is the same as the number of displacement sensors in the multiple displacement sensors; According to the unit load mass, the initial load mass of the balanced electric spindle is increased to obtain a loaded electric spindle, wherein the position where the load mass is increased is a load device connected to the balanced electric spindle; Acquire the current load speed of the loaded electric spindle, increase the speed of the current load speed, and when the current load speed is equal to the initial spindle speed, stop increasing the speed of the current load speed and measure the vibration displacement of the loaded electric spindle to obtain a target vibration displacement set; Acquire the current running load mass, and identify the maximum initial displacement and the maximum target displacement in the initial vibration displacement set and the target vibration displacement set, respectively, wherein the maximum initial displacement and the maximum target displacement are both vector synthetic displacements; Calculating the spindle rotation stiffness according to the maximum initial displacement, the maximum target displacement and the running load mass; Using the load electric spindle and the running load mass to update the balanced electric spindle and the initial load mass respectively, and returning to the step of increasing the load mass of the initial load mass of the balanced electric spindle according to the unit load mass, until the spindle rotation stiffness quantity obtained is not less than the preset reference stiffness quantity; The spindle rotation stiffness and the real-time measurement time are respectively summarized to obtain a spindle rotation stiffness set and a real-time measurement time set.

5. The optimal preload force analysis method for an electric spindle according to claim 4, characterized in that: The calculating the spindle rotation stiffness according to the maximum initial displacement, the maximum target displacement and the running load mass includes: Identify the maximum difference angle between the maximum initial displacement and the maximum target displacement, and calculate the spindle rotation stiffness according to the initial spindle speed, the maximum difference angle, the running load mass, the maximum initial displacement and the maximum target displacement, wherein the spindle rotation stiffness is expressed as: ； in, represents the spindle rotation stiffness, Indicates the running load mass, represents the maximum initial displacement, represents the maximum target displacement, represents the absolute value symbol, represents the cosine function, Indicates the maximum difference angle.

6. The optimal preload force analysis method for an electric spindle according to claim 5, characterized in that: The method of using an acoustic wave measurement unit to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set includes: Acquiring the acoustic-elastic coefficient of the acoustic-wave measurement unit, wherein the acoustic-elastic coefficient includes: the acoustic-elastic coefficient of a transverse wave and the acoustic-elastic coefficient of a longitudinal wave; Confirming an effective rotational position in the balanced electric spindle, identifying the total spindle length of the balanced electric spindle and the effective rotational length of the effective rotational position, respectively, and obtaining a measurement contact area between the acoustic wave measurement unit and the balanced electric spindle; The following operations are performed for each real-time measurement moment in the real-time measurement moment set: Based on the real-time measurement moment, the acoustic wave measuring unit is used to perform acoustic wave monitoring on the balanced electric spindle, wherein the acoustic wave monitoring process is that the acoustic wave measuring unit emits ultrasonic waves to the balanced electric spindle and records the propagation speed of the ultrasonic waves when propagating in the balanced electric spindle; Recording the sound wave propagation speed of the ultrasonic wave when it propagates in the balanced electric spindle during the sound wave monitoring process, wherein the sound wave propagation speed includes: longitudinal wave propagation speed and shear wave propagation speed; According to the acoustic wave propagation velocity, acoustic wave acoustoelastic coefficient, effective rotation length, total spindle length and measured contact area, the acoustic wave preload force is calculated using the following formula: ； in, Indicates the acoustic preload force, represents the total length of the main axis, represents the shear wave propagation speed, Represents the measured contact area, represents the effective rotation length, represents the shear wave acoustoelastic coefficient, represents the longitudinal wave acoustoelastic coefficient, represents the propagation speed of longitudinal waves; The acoustic wave preload forces are aggregated to obtain an acoustic wave preload force set.

7. The optimal preload force analysis method for an electric spindle according to claim 6, characterized in that: The piezoelectric measurement unit is used to perform piezoelectric measurement on the preload force of the balanced electric spindle to obtain a piezoelectric preload force set, including: Identifying a plurality of piezoelectric sensors of the piezoelectric measuring unit, wherein the number of the piezoelectric sensors is manually set, and the plurality of piezoelectric sensors are evenly mounted on the side surface of the bearing in the balancing electric spindle; The following operations are performed for each real-time measurement moment in the real-time measurement moment set: Starting the piezoelectric measuring unit and using the piezoelectric measuring unit to measure the pressure of the balancing electric spindle to obtain an original measured pressure set, wherein the number of original measured pressures in the original measured pressure set is the same as the number of piezoelectric sensors in the piezoelectric measuring unit; Identifying a first maximum pressure and a second maximum pressure in the original measured pressure set, and identifying a first measurement position and a second measurement position corresponding to the first maximum pressure and the second maximum pressure, respectively; Calculating the piezoelectric azimuth angles at the first measurement position and the second measurement position, and determining whether the piezoelectric azimuth angle is less than a preset standard azimuth angle; If the piezoelectric azimuth angle is not less than the standard azimuth angle, the piezoelectric preload force is calculated according to the first maximum pressure, the second maximum pressure and the piezoelectric azimuth angle, wherein the piezoelectric preload force is expressed as: ； in, represents the piezoelectric preload, Indicates the first extreme pressure, Indicates the second greatest pressure, represents the piezoelectric azimuth; If the piezoelectric azimuth angle is smaller than the standard azimuth angle, the first maximum pressure is recorded as the piezoelectric preload force; The piezoelectric preload forces are aggregated to obtain a piezoelectric preload force set.

8. The optimal preload force analysis method for an electric spindle according to claim 7, characterized in that: The identifying of the candidate preload line segment set and respectively confirming the candidate test environment group set in the spindle rotation stiffness set and the spindle temperature change set include: Performing line segment division on the acoustic wave preload force curve to obtain an acoustic wave line segment set, and identifying an acoustic wave preload force coefficient set and an acoustic wave time period set of the acoustic wave line segment set, wherein the acoustic wave preload force coefficient is the slope of the acoustic wave line segment, and the acoustic wave time period is the horizontal coordinate range of the acoustic wave line segment; Dividing the piezoelectric preload force curve into segments according to the acoustic wave time period set to obtain a piezoelectric line segment set, and identifying a piezoelectric preload force coefficient set of the piezoelectric line segment set; Extracting the acoustic wave preload coefficient and the piezoelectric preload coefficient from the acoustic wave preload coefficient set and the piezoelectric preload coefficient set respectively, and calculating the coefficient difference between the acoustic wave preload coefficient and the piezoelectric preload coefficient; Determine whether the coefficient difference is less than a preset standard deviation; If the coefficient difference is less than the standard deviation, respectively identifying candidate acoustic wave segments and candidate piezoelectric line segments of the acoustic wave preload coefficient and the piezoelectric preload coefficient, averaging the candidate acoustic wave segments and candidate piezoelectric line segments to obtain candidate preload line segments; Identify candidate acoustic wave time periods of candidate preload force line segments in the acoustic wave time period set, and confirm candidate temperature change groups and candidate rotational stiffness groups in the spindle temperature change set and spindle rotational stiffness set based on the candidate acoustic wave time periods; The candidate preload line segments, candidate change temperature groups and candidate rotational stiffness groups are respectively summarized to obtain a candidate preload line segment set, a candidate change temperature group set and a candidate rotational stiffness group set.

9. The optimal preload force analysis method for an electric spindle according to claim 8, characterized in that: The constructing of the optimal preload table based on the candidate preload line segment set and the candidate test environment group set includes: Extracting candidate preload line segments, candidate change temperature groups and candidate rotational stiffness groups from the candidate preload line segment set, candidate change temperature group set and candidate rotational stiffness group set respectively; Identifying the minimum change temperature and the maximum rotational stiffness in the candidate change temperature group and the candidate rotational stiffness group, respectively, and identifying the minimum temperature moment and the maximum stiffness moment of the minimum change temperature and the maximum rotational stiffness, respectively; Based on the minimum temperature moment and the maximum stiffness moment, confirming the temperature mapping preload and the stiffness mapping preload in the candidate preload line segment, calculating the median preload of the temperature mapping preload and the stiffness mapping preload, and recording the median preload as the optimal preload; Key-pairing the optimal preload force, the candidate temperature change group and the candidate rotational stiffness group to obtain an optimal preload force group, and summarizing the optimal preload force groups to obtain an optimal preload force group set; An optimal preload force table is drawn according to the optimal preload force group set, wherein one optimal preload force in the optimal preload force table corresponds to one candidate variable temperature group and one candidate rotational stiffness group.

10. An optimal preload force analysis system for an electric spindle, characterized in that: The system comprises: An electric spindle stiffness test module is used to receive a preload force analysis instruction, set an initial spindle speed based on the preload force analysis instruction, start a pre-built electric spindle to be tested based on the initial spindle speed, obtain a running electric spindle, wherein the speed of the running electric spindle is the initial spindle speed, perform rotational vibration balancing on the running electric spindle to obtain a balanced electric spindle, perform a rotational stiffness test on the balanced electric spindle to obtain a spindle rotational stiffness set and a real-time measurement time set, and measure a spindle change temperature set of the balanced electric spindle based on the real-time measurement time set; An acoustic wave preload force measurement module is used to start a pre-built preload force measurement unit, wherein the preload force measurement unit includes: an acoustic wave measurement unit and a piezoelectric measurement unit, and the acoustic wave measurement unit is an ultrasonic probe, and the piezoelectric measurement unit is a piezoelectric sensor, and the acoustic wave measurement unit is used to perform acoustic wave measurement of the preload force of the balanced electric spindle to obtain an acoustic wave preload force set, wherein the acoustic wave measurement unit is arranged on both sides of the balanced electric spindle; A preload force curve fitting module is used to perform piezoelectric measurement of the preload force of the balanced electric spindle using a piezoelectric measurement unit to obtain a piezoelectric preload force set, wherein the piezoelectric measurement unit is placed at the connection between the bearing and the spindle of the balanced electric spindle, and the preload force curves of the acoustic wave preload force set and the piezoelectric preload force set are respectively fitted according to the real-time measurement time set to obtain an acoustic wave preload force curve and a piezoelectric preload force curve; A preload table construction module is used to identify candidate preload line segment sets based on the acoustic preload curve and the piezoelectric preload curve, and to confirm candidate test environment groups in the spindle rotation stiffness set and the spindle change temperature set respectively, wherein the candidate test environment groups include: candidate change temperature groups and candidate rotation stiffness groups, and to construct an optimal preload table based on the candidate preload line segment sets and the candidate test environment groups.

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