Motorized spindle high-frequency iron loss modeling and iron loss fine analysis method

Abstract

The invention provides a high-frequency iron loss modeling and iron loss fine analysis method for an electric spindle, and belongs to the technical field of electric spindle design. The method comprises the following steps: analyzing the types of iron loss of the electric spindle under a high-frequency condition, including eddy current loss, magnetic hysteresis loss and residual loss; analyzing the optimal value of eddy current loss and population genetic record data according to a population genetic algorithm, analyzing magnetic hysteresis loss by using a minimum cell block decomposition method, analyzing residual loss data according to the operating temperature of the designed motorized spindle, and designing the motorized spindle by taking design parameters as initial parameters of population genetic and total loss as optimal design individuals. And finally, obtaining optimal individual and population genetic process data. According to the method, independent optimal design analysis is carried out on each loss, then optimal iterative analysis is carried out on all the losses, optimal result data obtained after iteration is analyzed to obtain iteration process data, and then reverse analysis is carried out on the iteration data to obtain design parameters of the motorized spindle, so that miniaturization, light weight and high performance are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric spindle design, and particularly to a high-frequency iron loss modeling and refined iron loss analysis method for an electric spindle. Background Art

[0002] With the increasing demand for high-performance power transmission devices in modern manufacturing, the electric spindle, as the core component of processing equipment such as numerically controlled machine tools, directly affects the machining accuracy and production efficiency. Traditional electric spindles have deficiencies in torque density, which limits their application scope and development potential. To overcome these problems, there is an urgent need to develop a new design method to improve the torque density of the electric spindle while ensuring its miniaturization, lightweight, and high performance.

[0003] Existing electric spindle designs are all carried out considering specific performances, but the size and corresponding high-frequency iron loss are not taken into account, resulting in the inability of the electric spindle to achieve miniaturization, lightweight, and high performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-frequency iron loss modeling and refined iron loss analysis method for an electric spindle to solve the technical problems mentioned in the background art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A high-frequency iron loss modeling and refined iron loss analysis method for an electric spindle, the method comprising the following steps:

[0007] Step 1: Analyze the types of iron losses under high-frequency conditions of the electric spindle, including eddy current loss, hysteresis loss, and residual loss;

[0008] Step 2: Analyze the optimal value of the eddy current loss and the population genetic record data according to the population genetic algorithm;

[0009] Step 3: Analyze the hysteresis loss using the minimum block decomposition method;

[0010] Step 4: Analyze the residual loss data according to the operating temperature of the designed electric spindle;

[0011] Step 5: Use the design parameters as the initialization parameters of the population genetics, and the total loss as the optimal design individual. Finally, obtain the optimal individual and the population genetic process data, and then obtain the design parameters of the electric spindle according to the genetic process data.

[0012] Furthermore, in step 1, in eddy current loss, when the magnetic flux changes through the magnetic material, a circulating current will be generated inside the material. The eddy current will cause energy to be dissipated in the form of heat. The higher the frequency, the higher the eddy current loss. Thinner and more insulated metal sheets are used to stack the core to increase the resistance of the eddy current path and reduce eddy current loss. In hysteresis loss, the energy loss caused by repeated reversal of magnetic domains inside the magnetic material. Each time the direction of the magnetic field changes, the magnetic domains need to be rearranged, which consumes energy and is converted into heat for release. The hysteresis loss is proportional to the area of ​​the hysteresis loop of the material. The higher the frequency, the higher the hysteresis loss. The residual loss includes the loss caused by the magnetostrictive effect and the resonance loss.

[0013] Furthermore, in step 2, the population is initialized with the range of loss measurement values ​​at different magnetic flux densities and frequencies, the eddy current loss data of the existing electric spindle is tested experimentally, and then genetic iteration is performed with the eddy current loss data as the genetic individual, and then the relatively optimal data of eddy current loss is designed based on the experimental data. In the iterative process, the iterative individual is compared with the relatively optimal data. When the difference between the value of the genetic individual and the relatively optimal data is the largest, it is the optimal genetic individual.

[0014] Furthermore, in step 3, the magnetic flux density distribution under the frequency and surface peak magnetic flux density is set, the core is divided into several small blocks along the thickness, the internal magnetic flux density of each small block is calculated, the hysteresis loss of each small block is calculated, and the total hysteresis loss is the superposition of the hysteresis losses of all small blocks.

[0015] Furthermore, in step 4, according to the highest design operating temperature and the selected material data, the RL type fractional derivative and loss statistics method are used to statistically analyze the residual loss of the electric spindle, and then a temperature effect nonlinear model is established based on the relationship between temperature and the loss caused by the magnetostrictive effect to obtain the residual loss size of the selected material under the operating temperature conditions.

[0016] Furthermore, in step 5, according to the requirements of designing the electric spindle, the initial setting parameters are first selected, and then the setting parameters are used as initialization, and the losses calculated in steps 2 to 4 are used as population input, and then iterations are performed to obtain the optimal design individual, and then based on the optimal design individual, the iterative recording process is reversely searched, and then the optimal design parameters are obtained based on the recording process.

[0017] Furthermore, the electric spindle includes a spindle mechanism, a heat dissipation component and an electric drive component. The heat dissipation component is arranged at one end of the spindle mechanism and embedded in the spindle mechanism. The electric drive component is arranged at one end of the heat dissipation component and passes through the spindle mechanism and the heat dissipation component.

[0018] Further, the main shaft mechanism includes a housing, a front bearing mount, a front bearing, a motor assembly, a rotating shaft, a rear bearing, and a rear bearing mount. The front bearing mount and the rear bearing mount are respectively arranged at both ends of the housing. The motor assembly is arranged inside the housing. The front bearing is arranged inside the front bearing mount. The rear bearing is arranged inside the rear bearing mount. The rotating shaft passes through the inside of the motor assembly and is respectively arranged on the front bearing and the rear bearing at both ends.

[0019] Further, the motor assembly includes a stator assembly, a rotor assembly, and a sheath. The stator assembly is arranged outside the rotor assembly. The sheath is arranged between the stator assembly and the rotor assembly. The rotating shaft is arranged inside the rotor assembly.

[0020] Further, an encoder is arranged on the rotating shaft. The rotating shaft is a hollow rotating shaft, and a chuck assembly is arranged at the front end of the rotating shaft.

[0021] Further, the sheath is a carbon fiber sheath, and both the front bearing and the rear bearing are magnetic levitation bearings.

[0022] Further, the heat dissipation assembly includes a heat dissipation box and a cooling structure. The heat dissipation box is arranged at both ends of the cooling structure. The cooling structure is arranged inside the housing of the stator assembly.

[0023] Further, the cooling structure is arranged as a Z-shaped annular water jacket cooling structure. The water jacket cooling structure is connected to the heat dissipation box to keep the average temperature of the motor below 60 degrees Celsius.

[0024] Further, the electric drive assembly includes a rear seat, a cylinder power component, a power ring, a mount, a push rod release mechanism, and a push rod. The power ring is arranged on the cylinder power component. The push rod release mechanism is connected to the power ring and the push rod. One end of the push rod is arranged on the power ring. The mount is arranged at the rear end of the cylinder power component. The rear seat is arranged on the heat dissipation assembly. The push rod release mechanism is arranged on the rear seat. The push rod passes through the rear seat and is arranged inside the rotating shaft.

[0025] Further, when designing the electric spindle, several physical field combined simulations are adopted, including electromagnetic design, heat dissipation design, and mechanical mechanics simulation design. At the same time, the method of harmonic pole cutting and harmonic injection is used to improve the torque density of the permanent magnet motor system.

[0026] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects:

[0027] (1) By separately performing optimal design analysis on each loss, then performing optimal iterative analysis on all the losses, analyzing the optimal result data after iteration to obtain the iterative process data, and then performing reverse analysis on the iterative data to obtain the design parameters of the electric spindle, the present invention realizes miniaturization, lightweight, and high performance.

[0028] (2) The rotational speed and torque of the motorized spindle of the present invention have been greatly improved. The rated rotational speed reaches 150,000 rpm, and the continuous torque is 0.1273 Nm. By performing a refined analysis of the iron loss and optimizing the dimensions, the efficiency of the motorized spindle is improved. The coupling relationship between the motor and the controller is fully considered to achieve high-speed precision dynamic control and enhance the overall efficiency of the motor system. The motor has higher efficiency, a wider speed regulation range, and better performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flowchart of the method of the present invention;

[0030] Figure 2 is a schematic structural diagram of the motorized spindle of the present invention;

[0031] Figure 3 is a schematic diagram of the heat dissipation structure of the present invention;

[0032] Figure 4 is a schematic diagram of the gas path structure of the present invention;

[0033] Figure 5 is a comparison chart of the rotational speed and torque of the present invention and the existing motorized spindle.

[0034] In the drawings, 1 - housing, 2 - front bearing mounting seat, 3 - front bearing, 4 - chuck assembly, 5 - rotating shaft, 6 - sheath, 7 - stator assembly, 8 - rotor assembly, 9 - heat dissipation box, 10 - encoder, 11 - rear bearing, 12 - rear bearing mounting seat, 13 - rear seat, 14 - cylinder power component, 15 - power ring, 16 - mounting seat, 17 - push rod release mechanism, 18 - push rod. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the following preferred embodiments are given with reference to the accompanying drawings for further detailed description of the present invention. However, it should be noted that many details listed in the specification are only for enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0036] As Figure 1 shown, a high-frequency iron loss modeling and refined iron loss analysis method for a motorized spindle, the method comprising the following steps:

[0037] Step 1: Analyze the types of iron losses under high-frequency conditions of the motorized spindle, including eddy current loss, hysteresis loss, and residual loss. In eddy current loss, when the magnetic flux changes through a magnetic material, a circulating current is generated inside the material. Eddy currents cause energy to dissipate in the form of heat. The higher the frequency, the higher the eddy current loss. The iron core is made of stacked thin and mutually insulated metal sheets to increase the resistance of the eddy current path and reduce eddy current loss. In hysteresis loss, it is the energy loss caused by the repeated reversal of magnetic domains inside the magnetic material. Each time the magnetic field direction changes, the magnetic domains need to be re-aligned, consuming energy and releasing it as heat. Hysteresis loss is proportional to the area of the hysteresis loop of the material. The higher the frequency, the higher the hysteresis loss. Residual loss includes the loss caused by the magnetostrictive effect and resonance loss.

[0038] Step 2: Analyze the optimal value of eddy current loss and the population genetic record data according to the population genetic algorithm. Initialize the population with the value ranges of loss measurement values at different magnetic flux densities and different frequency points. Based on the experimental test data of the eddy current loss of the existing motorized spindle, then use the eddy current loss data as genetic individuals for genetic iteration. Then, design the relatively optimal data of eddy current loss according to the experimental data. During the iteration process, compare the iterative individuals with the relatively optimal data. When the difference between the value of the genetic individual and the relatively optimal data is the largest, it is the optimal genetic individual.

[0039] Step 3: Analyze the hysteresis loss using the minimum block decomposition method. Set the magnetic flux density distribution under the frequency and surface peak magnetic flux density. Divide the iron core into several small blocks along the thickness, calculate the internal magnetic flux density of each small block, calculate the hysteresis loss of each small block, and the total hysteresis loss is the superposition of the hysteresis losses of all small blocks.

[0040] Step 4: Analyze the residual loss data according to the operating temperature of the designed motorized spindle. According to the highest designed operating temperature and the selected material data, use the R-L type fractional derivative and the loss statistical method to statistically analyze the residual loss of the motorized spindle. Then, establish a temperature effect nonlinear model based on the relationship between temperature and the loss caused by the magnetostrictive effect to obtain the magnitude of the residual loss of the selected material under the operating temperature conditions.

[0041] Step 5: Use the design parameters as the initialization parameters of population genetics, and the total loss as the optimal design individual. Finally, obtain the optimal individual and the population genetic process data, and then obtain the design parameters of the motorized spindle according to the genetic process data. According to the requirements of designing the motorized spindle, first select the initial set parameters, then use the set parameters as the initialization, use the losses calculated in Steps 2 - 4 as the population input, and then perform iteration to obtain the optimal design individual. Then, according to the optimal design individual, inversely search for the iteration record process, and then obtain the optimal design parameters according to the record process.

[0042] As Figures 2 - 4As shown in the figure, the electric spindle includes a spindle mechanism, a heat dissipation component, and an electric drive component. The heat dissipation component is arranged at one end of the spindle mechanism and is embedded in the spindle mechanism. The electric drive component is arranged at one end of the heat dissipation component and passes through the spindle mechanism and the heat dissipation component. The spindle mechanism mainly plays a role in driving rotation. The heat dissipation component mainly dissipates heat inside the spindle mechanism. Then, the electric drive component mainly realizes the forward and backward movements.

[0043] In the embodiment of the present invention, the spindle mechanism includes a housing 1, a front bearing mounting seat 2, a front bearing 3, a motor assembly, a rotating shaft 5, a rear bearing 11, and a rear bearing mounting seat 12. The front bearing mounting seat 2 and the rear bearing mounting seat 12 are respectively arranged at both ends of the housing 1. The motor assembly is arranged inside the housing 1. The front bearing 3 is arranged inside the front bearing mounting seat 2. The rear bearing 11 is arranged inside the rear bearing mounting seat 12. The rotating shaft 5 passes through the inside of the motor assembly and is respectively arranged on the front bearing 3 and the rear bearing 11 at both ends. The motor assembly includes a stator assembly 7, a rotor assembly 8, and a sheath 6. The stator assembly 7 is arranged outside the rotor assembly 8. The sheath 6 is arranged between the stator assembly 7 and the rotor assembly 8. The rotating shaft 5 is arranged inside the rotor assembly 8.

[0044] In the embodiment of the present invention, an encoder 10 is arranged on the rotating shaft 5. The rotating shaft 5 is a hollow rotating shaft, and a chuck assembly 4 is arranged at the front end of the rotating shaft 5.

[0045] In the embodiment of the present invention, the sheath 6 is a carbon fiber sheath, and both the front bearing 3 and the rear bearing 11 are magnetic levitation bearings. The interference fit between the rotor carbon fiber sheath and the permanent magnet is 0.06 mm, and the force on the permanent magnet is much lower than its tensile strength (the tensile strength of neodymium iron boron is in the range of 80 - 140 MPa).

[0046] In the embodiment of the present invention, the heat dissipation component includes a heat dissipation box 9 and a cooling structure. The heat dissipation box 9 is arranged at both ends of the cooling structure, and the cooling structure is arranged inside the housing of the stator assembly 7.

[0047] In the embodiment of the present invention, the cooling structure is set as a Z-shaped annular water jacket cooling structure. The water jacket cooling structure is connected to the heat dissipation box 9 to keep the average temperature of the motor below 60 degrees Celsius. By adopting the Z-shaped annular water jacket cooling structure of the stator housing and optimizing the size of the water channel, heat can be taken away with the maximum efficiency.

[0048] In the embodiment of the present invention, the electric drive assembly includes a rear seat 13, a cylinder power member 14, a power ring 15, a mounting seat 16, a push rod release mechanism 17, and a push rod 18. The power ring 15 is arranged on the cylinder power member 14. The push rod release mechanism 17 is connected to the power ring 15 and the push rod 18. One end of the push rod 18 is arranged on the power ring 15. The mounting seat 16 is arranged at the rear end of the cylinder power member 14. The rear seat 13 is arranged on the heat dissipation assembly. The push rod release mechanism 17 is arranged on the rear seat 13. The push rod 18 passes through the rear seat 13 and is arranged in the rotating shaft 5.

[0049] In the embodiment of the present invention, when designing the electric spindle, several physical field combined simulations are adopted, including electromagnetic design, heat dissipation design, and mechanical mechanics simulation design. At the same time, the methods of harmonic pole reduction and harmonic injection are used to improve the torque density of the permanent magnet motor system. The coupling relationship between the motor and the controller is fully considered, so as to realize high-speed precision dynamic control and improve the overall efficiency of the motor system. Through refined analysis of iron loss and optimization of dimensions, the efficiency of the electric spindle is improved, and an efficient and energy-saving electric spindle brand is created.

[0050] As Figure 5 shown, Figure 5 B is the result data of this application, Figure 5 A is the data of the existing Xifeng brand motor electric spindle. The torque of this application is much larger than that of the existing electric spindle, and at the same time, the speed is also higher, achieving a step breakthrough.

[0051] The rated voltage (Vdc) of this electric spindle is 208, the continuous power (kW) is 2.0, the maximum dynamic runout (μm) is 7 (150,000 rpm), the continuous torque (Nm) is 0.1273, the continuous load (Nm) is 2000, the rated speed (rpm) is 150,000, the maximum speed (rpm) is 160,000, the operating temperature range (°C) is -40 to +65, the locked-rotor torque (Nm) is 7.47, the maximum fixture torque (Nm) is 2.3, the maximum leakage current (mA) is 0.01, the reference mass (kg) is 2.5, and the reference external dimension (mm) is Φ50×200

[0052] Matters not covered by the present invention are well-known technologies.

[0053] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A high-frequency iron loss modeling and iron loss refinement analysis method for an electric spindle, characterized by: The method comprises the following steps: Step 1: Analyze the iron loss categories of the electric spindle under high frequency conditions, including eddy current loss, hysteresis loss and residual loss; Step 2: Analyze the optimal value of eddy current loss and population genetic record data according to the population genetic algorithm; Step 3: Analyze hysteresis loss using the minimum block decomposition method; Step 4: Analyze the remaining loss data according to the designed operating temperature of the electric spindle; Step 5: Use the design parameters as the initialization parameters of population genetics, and the total loss as the optimal design individual. Finally, the optimal individual and population genetic process data are obtained, and then the design parameters of the electric spindle are obtained based on the genetic process data.

2. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 1 is characterized in that: In step 1, in eddy current loss, when the magnetic flux changes through the magnetic material, a circulating current will be generated inside the material. The eddy current will cause energy to dissipate in the form of heat. The higher the frequency, the higher the eddy current loss. Thinner and more insulated metal sheets are used to stack the core to increase the resistance of the eddy current path and reduce eddy current loss. In hysteresis loss, the energy loss caused by repeated reversal of magnetic domains inside the magnetic material. Each time the direction of the magnetic field changes, the magnetic domains need to be rearranged, which consumes energy and converts it into heat for release. Hysteresis loss is proportional to the area of ​​the hysteresis loop of the material. The higher the frequency, the higher the hysteresis loss. The residual loss includes the loss caused by the magnetostrictive effect and the resonance loss.

3. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 1 is characterized in that: In step 2, the population is initialized with the range of loss measurement values ​​at different magnetic flux densities and frequencies. The eddy current loss data of the existing electric spindle is tested experimentally, and then genetic iteration is performed with the eddy current loss data as the genetic individual. Then, the relatively optimal data of eddy current loss is designed based on the experimental data. In the iterative process, the iterative individual is compared with the relatively optimal data. When the difference between the value of the genetic individual and the relatively optimal data is the largest, it is the optimal genetic individual.

4. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 1 is characterized in that: In step 3, the magnetic flux density distribution under the frequency and surface peak magnetic flux density is set, the core is divided into several small blocks along the thickness, the internal magnetic flux density of each small block is calculated, the hysteresis loss of each small block is calculated, and the total hysteresis loss is the superposition of the hysteresis losses of all small blocks.

5. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 1 is characterized in that: In step 4, according to the highest design operating temperature and the selected material data, the RL type fractional derivative and loss statistics method are used to calculate the residual loss of the electric spindle. Then, according to the relationship between temperature and the loss caused by magnetostrictive effect, a temperature effect nonlinear model is established to obtain the residual loss of the selected material under the operating temperature conditions.

6. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 1 is characterized in that: In step 5, according to the requirements of designing the electric spindle, the initial setting parameters are first selected, and then the setting parameters are used as initialization, and the losses calculated in steps 2 to 4 are used as population input, and then iterations are performed to obtain the optimal design individual, and then based on the optimal design individual, the iterative recording process is reversely searched, and then the optimal design parameters are obtained based on the recording process.

7. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 1 is characterized in that: The electric spindle comprises a spindle mechanism, a heat dissipation component and an electric drive component. The heat dissipation component is arranged at one end of the spindle mechanism and embedded in the spindle mechanism. The electric drive component is arranged at one end of the heat dissipation component and passes through the spindle mechanism and the heat dissipation component. The spindle mechanism comprises a housing (1), a front bearing mounting seat (2), a front bearing (3), a motor assembly, a rotating shaft (5), a rear bearing (11) and a rear bearing mounting seat (12); the front bearing mounting seat (2) and the rear bearing mounting seat (12) are respectively arranged at two ends of the housing (1); the motor assembly is arranged inside the housing (1); the front bearing (3) is arranged inside the front bearing mounting seat (2); the rear bearing (11) is arranged inside the rear bearing mounting seat (12); the rotating shaft (5) passes through the interior of the motor assembly, and its two ends are respectively arranged on the front bearing (3) and the rear bearing (11).

8. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 7 is characterized in that: The motor assembly comprises a stator assembly (7), a rotor assembly (8) and a sheath (6); the stator assembly (7) is arranged on the outside of the rotor assembly (8), the sheath (6) is arranged between the stator assembly (7) and the rotor assembly (8), and the rotating shaft (5) is arranged inside the rotor assembly (8).

9. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 8 is characterized in that: An encoder (10) is arranged on the rotating shaft (5), the rotating shaft (5) is a hollow rotating shaft, and a chuck assembly (4) is arranged at the front end of the rotating shaft (5); The sheath (6) is a carbon fiber sheath, and the front bearing (3) and the rear bearing (11) both use magnetic bearings.

10. The high-frequency iron loss modeling and iron loss refinement analysis method of an electric spindle according to claim 9 is characterized in that: The heat dissipation assembly comprises a heat dissipation box (9) and a cooling structure, wherein the heat dissipation box (9) is arranged at both ends of the cooling structure, and the cooling structure is arranged in a housing of the stator assembly (7); The cooling structure is configured as a Z-shaped annular water jacket cooling structure, and the water jacket cooling structure is connected to a heat sink (9) to maintain an average temperature of the motor below 60 degrees Celsius; The electric drive assembly comprises a rear seat (13), a cylinder power member (14), a power ring (15), a mounting seat (16), a push rod release mechanism (17) and a push rod (18); the power ring (15) is arranged on the cylinder power member (14); the push rod release mechanism (17) is connected to the power ring (15) and the push rod (18); one end of the push rod (18) is arranged on the power ring (15); the mounting seat (16) is arranged at the rear end of the cylinder power member (14); the rear seat (13) is arranged on the heat dissipation assembly; the push rod release mechanism (17) is arranged on the rear seat (13); the push rod (18) passes through the rear seat (13) and is arranged in the rotating shaft (5).

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