A thermo-mechanical coupling simulation analysis method for B-axis power tool post

Abstract

This invention proposes a thermo-mechanical coupling simulation analysis method for a B-axis powered tool holder, comprising the following steps: Step 1, constructing and simplifying a three-dimensional geometric model of the tool holder; Step 2, determining the heat source type and heat generation rate; Step 3, setting heat transfer boundary conditions; Step 4, establishing a thermo-mechanical coupling finite element model; Step 5, applying thermal loads and solving for the temperature field; Step 6, applying mechanical loads and constraints; Step 7, solving for the thermo-mechanical coupling deformation field; Step 8, comparative analysis. The method of this invention is standardized and computationally accurate, comprehensively considering the coupling effect of thermal and mechanical loads, and accurately predicting the temperature and deformation fields of the tool holder. This invention is applicable to the prediction of thermal deformation of B-axis powered tool holder structures, identification of key heat sources, and optimization of cooling schemes, and can be widely applied to the design, performance optimization, and machining accuracy improvement of tool holders in five-axis linkage milling and turning machining centers.

Description

Technical Field

[0001] This invention relates to the field of thermal characteristic analysis technology for high-end CNC machine tools, specifically to a thermal-mechanical coupling simulation analysis method for the B-axis power tool post of a milling and turning machining center. Background Technology

[0002] The B-axis powered tool post is a core functional component of a five-axis CNC milling and turning machining center. Integrating an electric spindle and torque motor, it enables continuous tool oscillation and powered cutting, directly determining the machining center's accuracy, efficiency, and machining range. During actual machining, the electric spindle bearings, stator and rotor, and torque motor within the B-axis powered tool post continuously generate significant heat, creating a multi-heat source coupling distribution. This heat transfer to various structural components of the tool post triggers thermal deformation, leading to tool posture deviation and affecting machining accuracy. Thermal errors account for 40%–60% of the total error in a machining system. Therefore, accurately predicting the temperature and deformation field distribution of the B-axis powered tool post under thermo-mechanical coupling is of significant engineering application value and theoretical guiding significance for optimizing tool post structural design, identifying key heat sources, developing reasonable cooling schemes, and achieving thermal error compensation.

[0003] In existing technologies, finite element simulation methods have been widely used for the thermal characteristic analysis of key CNC machine tool components such as spindles and tilting milling heads. However, current thermal simulation analysis methods for B-axis power tool holders still have many shortcomings: most methods only consider the influence of thermal loads, ignoring the superimposed effects of cutting forces, gravity, and other mechanical loads on the deformation of the tool holder structure, leading to deviations between simulation results and actual working conditions; the modeling of the heat generation mechanism of multiple heat sources such as electric spindle bearings, stators, rotors, and torque motors is not refined enough, lacking a unified standard for calculating heat generation rate, making it difficult to accurately reflect the actual heat generation characteristics of each heat source; at the same time, there is a lack of a systematic simulation process for the thermal-structural-mechanical coupling of the tool holder assembly as a whole and all key components such as the electric spindle, torque motor, housing, and cooling water jacket, and the boundary conditions are not closely aligned with actual assembly and working conditions, further reducing the accuracy and reliability of the simulation analysis. Therefore, there is an urgent need for a thermal-mechanical coupling simulation analysis method for B-axis power tool holders that can comprehensively reflect heat source distribution, heat transfer boundaries, mechanical boundaries, and coupling effects, and has a standardized process and accurate calculations. Summary of the Invention

[0004] To address the problems existing in the background technology, this invention proposes a thermo-mechanical coupling simulation analysis method for a B-axis power tool post, comprising the following steps:

[0005] Step 1: Construct and simplify the 3D geometric model of the tool holder. Based on the actual structure of the B-axis power tool holder, a three-dimensional geometric model including the electric spindle, torque motor, housing, and cooling water jacket was established; threaded holes, bolt holes, chamfers, fillets, and non-load-bearing lines were deleted to simplify the model. Step 2: Determine the type of heat source and the heat generation rate The main heat sources of the tool post are identified as the electric spindle stator, electric spindle rotor, electric spindle front bearing, electric spindle rear bearing, B-axis torque motor stator, and B-axis torque motor rotor; a unified formula is used to calculate the heat generation rate of each heat source. Step 3: Set heat transfer boundary conditions The forced convection heat transfer inside the tool holder and the natural convection heat transfer outside were clearly defined; the convective heat transfer coefficient was calculated using the Nusselt number correlation method. and assign corresponding heat exchange surfaces; Step 4: Establish a thermo-mechanical coupled finite element model The simplified geometric model is imported into the finite element software, the material properties of each component are defined, the mesh is automatically generated, and the heat source area, bearing area, and tool tip are locally refined. Step 5: Apply thermal load and solve for the temperature field. Using the heat generation rate as a volume heat source and the convective heat transfer coefficient as a surface load, steady-state or transient thermal analysis is performed to obtain the overall temperature field of the tool holder. Step 6: Apply mechanical loads and constraints The temperature field is mapped as a thermal load onto the tool holder structure model, while milling force and gravity load are applied, and fixed constraints are applied to the tool holder mounting surface. Step 7: Solve for the thermo-mechanical coupled deformation field In the finite element analysis software, a thermo-structural coupling analysis was performed to solve the comprehensive deformation field of the B-axis dynamic tool holder under the combined action of thermal and mechanical loads. After the analysis was completed, the displacement fields of each key part of the tool holder in the X, Y, and Z directions were extracted to identify the location and amount of maximum deformation of the tool holder structure and to clarify the deformation distribution law in each direction. Step 8: Comparative Analysis Set up working conditions with only thermal load and working conditions with thermal load, milling force and gravity load, compare the difference in the deformation of the tool holder structure under the two working conditions, calculate the rate of change of deformation, and determine whether the influence of mechanical load on the thermal deformation of the tool holder is negligible.

[0006] Preferably, in step 2, the heat generation rate of the electric spindle stator, electric spindle rotor, torque motor stator, and torque motor rotor is determined by... calculate; in, ΔP P1 represents the power loss of the heat source, and P2 represents the rated power of the heat source component. η For the working efficiency of the heat source components. The heat generation rate of the heat source. The volume of the heat source component; The bearing heat generation rate is calculated based on the friction torque formula. The result is obtained through conversion.

[0007] Preferably, the formula for calculating the frictional torque is as follows: ; in, The total frictional torque of the bearing. For bearing lubrication-related torques, For the load-related torque of the bearing, The bearing lubrication friction coefficient, The bearing's rotational speed. The average diameter of the bearing. The bearing load friction coefficient, This refers to the radial load on the bearing; The heat generation rate of the bearing is calculated from the total frictional torque, and combined with the bearing volume, the final heat generation rate of the bearing is obtained.

[0008] Preferably, in step 3, the convective heat transfer coefficient The calculation process is as follows: First calculate the Reynolds number And Prandtl :

[0009] in, The average velocity of the fluid; This refers to the convection gap height. The fluid's kinematic viscosity; Specific heat capacity of the fluid; For fluid dynamic viscosity; Thermal conductivity of the fluid; Then, choose the Nusselt number formula based on the magnitude of the Reynolds number:

[0010] Finally, the convective heat transfer coefficient is calculated based on the Nusselt number. :

[0011] in, The characteristic length is determined based on the actual structure of the heat exchange surface; Based on the actual assembly relationship of the B-axis power tool post, the calculated convective heat transfer coefficients are assigned to the corresponding heat transfer surfaces to complete the setting of heat transfer boundary conditions.

[0012] Preferably, in step 4, the mesh type is a tetrahedral or hexahedral mesh, and the mesh distortion rate is ≤5%.

[0013] Preferably, step 5 specifically comprises: The heat generation rate of each heat source is applied as a volume heat source to the corresponding heat source component. The calculated convective heat transfer coefficient is applied to the corresponding heat transfer surface. At the same time, the ambient temperature is set to the actual working ambient temperature of the tool holder. The heat conduction relationship between each component is defined, where the contact surface is set as thermal coupling and the gap surface is set as thermal resistance. Subsequently, steady-state or transient thermal analysis was performed to obtain the overall temperature field distribution cloud map of the B-axis power tool post, clarifying the temperature distribution pattern and the location of the highest temperature in each part.

[0014] Preferably, in step 6, the milling force is calculated based on actual machining parameters or obtained by experimental measurement, the gravity load is applied in the form of gravitational acceleration of 9.8 m / s², and the fixed constraint restricts all degrees of freedom of the mounting surface.

[0015] Preferably, in step 8, when the rate of change of deformation after the mechanical load is superimposed is less than 1%, it is determined that the influence of the mechanical load on thermal deformation is negligible.

[0016] The beneficial effects of this invention are as follows: 1. The method for calculating the heat generation rate of multiple heat sources in electric spindles and torque motors has been unified. At the same time, the analytical model of bearing frictional heat has been refined. The heat generation rate is accurately calculated by combining the working characteristics of each heat source. This solves the problems of inconsistent heat generation rate calculation and imprecise modeling in the existing technology and improves the accuracy of heat source modeling. 2. Complete boundary conditions for forced convection and natural convection heat transfer were established. The convective heat transfer coefficient of each heat transfer surface was accurately calculated by the Nusselt number correlation method. Boundary conditions were set in combination with the actual assembly and working conditions of the tool holder, which improved the physical consistency and accuracy of the temperature field simulation. 3. For the first time, the coupling effect of thermal load, milling force and gravitational field was considered simultaneously in the overall simulation of the B-axis power tool post. By setting up comparative working conditions, the negligible influence of mechanical load was verified, which provides a reliable basis for simplifying the simulation model and improving the simulation efficiency in the future. 4. It can accurately predict the thermal deformation distribution of the tool post in the X, Y, and Z directions. In particular, it can identify the Z-direction deformation as the main component, clarify the location of the maximum deformation and the deformation law, and provide key references for thermal error compensation, structural optimization and cooling scheme design of the B-axis power tool post, which helps to improve the machining accuracy of the milling and turning machining center. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the analytical method of the present invention; Figure 2 This is a schematic diagram of the overall temperature field of the B-axis power tool post in the method of the present invention; Figure 3 This is a schematic diagram of the temperature field distribution in the independent simulation of the electric spindle of this invention; Figure 4 This is a schematic diagram of the thermal-mechanical coupling simulation results of the B-axis power tool holder of the present invention. Detailed Implementation

[0018] To make the present invention clearer and more understandable, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the given embodiments are only one or more of the implementation methods and do not represent all embodiments.

[0019] In this article, terms such as "inner," "outer," "upper," and "lower" are established based on the positional relationships shown in the attached drawings. Depending on the attached drawings, the corresponding positional relationships may also change. Therefore, they should not be interpreted as an absolute limitation on the scope of protection.

[0020] This embodiment uses a B-axis power tool post equipped with an ES-B20 torque motor and an ES-20 electric spindle as the simulation object, combined with the attached... Figure 1 - Appendix Figure 4 This paper describes a thermo-mechanical coupling simulation analysis method for a B-axis power tool holder, which includes the following steps: Step 1: Construct and simplify the 3D geometric model of the tool holder. Based on the actual structural dimensions and assembly relationships of the B-axis power tool holder, a three-dimensional geometric model including the electric spindle, ES-B20 torque motor, tool holder body, and cooling water jacket was created using SolidWorks software. Redundant structures that do not affect structural stiffness, heat conduction, and mechanical properties, such as threaded holes, bolt holes, chamfers, fillets, and non-load-bearing lines, were deleted from the model. The core load-bearing structure, heat source components, and heat exchange components were retained, thus simplifying the model. The simplified model can ensure the quality of subsequent mesh generation and improve simulation efficiency.

[0021] Step 2: Determine the type of heat source and the heat generation rate The main heat sources of the tool post are identified as the electric spindle stator, electric spindle rotor, electric spindle front bearing, electric spindle rear bearing, B-axis torque motor stator, and B-axis torque motor rotor; the heat generation rate of each heat source is calculated using a unified formula. The stator heat generation rate of the electric spindle is 408759.12 W / m³, the rotor heat generation rate is 998810.94 W / m³, the stator heat generation rate of the B-axis torque motor is 192854.14 W / m³, the rotor heat generation rate is 52868.85 W / m³, the front bearing heat generation rate is 3332825.49 W / m³, and the rear bearing heat generation rate is 3138133.15 W / m³.

[0022] Step 3: Set heat transfer boundary conditions The forced convection heat transfer inside the tool holder and the natural convection heat transfer outside are clearly defined. Forced convection heat transfer occurs between the electric spindle stator-rotor gap and inside the cooling water jacket, while natural convection heat transfer occurs between the tool holder housing and the external environment. Using the Nusselt number correlation method, combined with fluid parameters under actual operating conditions (such as cooling water temperature and flow rate), the convective heat transfer coefficients of each heat exchange surface are calculated: the convective heat transfer coefficient between the electric spindle stator-rotor gap is taken as 266.3 W / (m²·℃), and the convective heat transfer coefficient at the contact surface between the electric spindle stator and the cooling water jacket is... The coefficients are set to 2000 W / (m²·℃), the convective heat transfer coefficient of the B-axis stator-rotor gap is set to 212.27 W / (m²·℃), the convective heat transfer coefficient of the contact surface between the B-axis stator and the cooling water jacket is set to 2626 W / (m²·℃), the natural convection heat transfer coefficient of the outer surface of the electric spindle housing is set to 9 W / (m²·℃), and the natural convection heat transfer coefficient of the outer surface of the B-axis housing is set to 5 W / (m²·℃). The above convective heat transfer coefficients are applied to the corresponding heat transfer surfaces to complete the heat transfer boundary condition setting.

[0023] Step 4: Establish a thermo-mechanical coupled finite element model The simplified geometric model was imported into the finite element software, and the material properties of each component were defined: the electric spindle and torque motor rotor were made of 40Cr material, the stator was made of silicon steel sheet, the tool holder housing was made of HT200 gray cast iron, and the cooling water jacket was made of 304 stainless steel. The density, elastic modulus, Poisson's ratio, thermal conductivity, and specific heat capacity of each material were set according to the actual material parameters. The automatic mesh generation function was used to mesh the model, and the electric spindle stator and rotor, torque motor stator and rotor, front and rear bearings, and tool tip were locally meshed. The mesh distortion rate was controlled within 3% to meet the simulation accuracy requirements. Among them, tetrahedral or hexahedral meshes were selected.

[0024] Step 5: Apply thermal load and solve for the temperature field. The heat generation rate of each heat source is applied as a volume heat source to the corresponding heat source components (electric spindle stator and rotor, torque motor stator and rotor, front and rear bearings). The convective heat transfer coefficient is applied to the corresponding heat transfer surface. The ambient temperature is set to 25℃. The contact surface of each component is defined as thermal coupling and the gap surface as thermal resistance. Steady-state thermal analysis is performed to obtain the overall temperature field distribution of the tool holder. The highest temperature point is at the front bearing of the electric spindle, with a maximum temperature of 65.702℃.

[0025] Step 6: Apply mechanical loads and constraints The temperature field is mapped as a thermal load onto the tool holder structure model. The milling force is calculated based on the actual machining parameters (cutting speed 120m / min, feed rate 0.2mm / r, depth of cut 2mm) and applied to the contact area between the tool and the workpiece. A gravitational acceleration of 9.8m / s² is applied, vertically downward. Fixed constraints are applied at the mounting surfaces of the tool holder and the machine tool body to restrict all degrees of freedom. Specifically, based on the actual machining parameters, the magnitude and direction of the milling force are obtained through the cutting force calculation formula or experimental measurement, and then applied to the contact area between the tool and the workpiece. Inertial load: A gravitational acceleration of 9.8 m / s² is applied to the entire tool holder assembly structure, vertically downward, to simulate the effect of the tool holder's own weight; Based on the actual installation relationship between the B-axis power tool post and the machine tool body, a fixed constraint is applied to the mounting surface of the tool post to restrict all degrees of freedom of the mounting surface, simulating the fixed state of the tool post during actual operation.

[0026] Step 7: Solve for the thermo-mechanical coupled deformation field A thermo-structural coupling analysis was performed in the finite element analysis software to solve the comprehensive deformation field of the B-axis power tool holder under the combined action of thermal and mechanical loads. After the analysis, the displacement field data of each key part of the tool holder in the X, Y, and Z directions were extracted to identify the location and amount of maximum deformation of the tool holder structure and to clarify the deformation distribution law in each direction. In this embodiment, the milling cutter position is the point of maximum deformation, and the maximum comprehensive deformation is 118.99 μm.

[0027] Step 8: Comparative Analysis We set up working conditions with only thermal load and working conditions with thermal load, milling force and gravity load, compared the difference in the deformation of the tool holder structure under the two working conditions, calculated the rate of change of deformation, and determined whether the influence of mechanical load on the thermal deformation of the tool holder can be ignored, so as to provide a theoretical basis for simplifying the simulation model and improving the simulation efficiency. The comparison results show that after superimposing milling force and gravity, the deformation of the tool holder changes by less than 0.5% compared to the deformation when only thermal load is applied. This indicates that the influence of mechanical load on the thermal deformation of this type of B-axis power tool holder is negligible. Subsequent simulations can be simplified to a simulation model with only thermal load applied, thus improving simulation efficiency.

[0028] For the two simulation conditions, Condition 1: only thermal load is applied, without milling force and gravity, and the thermal deformation of the tool holder is solved; Condition 2: thermal load, milling force and gravity are applied simultaneously, and the comprehensive deformation of the tool holder is solved.

[0029] To further clarify the impact of key heat sources on tool holder deformation, an independent simulation was performed on the electric spindle. The maximum deformation of the electric spindle was found to be 106.35 μm, indicating that the heat generated by the electric spindle itself is the main source of thermal deformation of the tool holder. The heat generated by the torque motor and the tool holder housing contributes approximately 12 μm to the deformation of the tool holder. At the same time, it was found that the maximum deformation in the X direction is located at the end of the spindle, the maximum deformation in the Y direction is located at the connection between the housing and the spindle, and the maximum deformation in the Z direction is located at the milling cutter and has the largest value. This indicates that the Z direction is the dominant direction of thermal deformation of the tool holder, providing a key reference for subsequent thermal error compensation.

[0030] Specifically, in step 2, the heat generation rates of the electric spindle stator, electric spindle rotor, torque motor stator, and torque motor rotor are determined by... calculate; in, ΔP P1 is the power loss of the heat source (W), and P2 is the rated power of the heat source component (W). η For the working efficiency of the heat source components. The heat generation rate of the heat source (W / m³). The volume (m³) of the heat source component. The bearing heat generation rate is calculated based on the friction torque formula. The result is obtained through conversion.

[0031] Specifically, the formula for calculating the frictional torque is as follows: ; in, The total frictional torque of the bearing is (N·mm). The bearing lubrication-related torque (N·mm). The load-related torque of the bearing is (N·mm). The bearing lubrication friction coefficient, The bearing speed (r / min) is given. The bearing's average diameter (mm) is given. The bearing load friction coefficient, The radial load (N) of the bearing; For the front and rear bearings of the electric spindle, the heat generation mainly comes from the frictional torque. The heat generation rate of the bearing is calculated from the total frictional torque and, combined with the bearing volume, the final heat generation rate of the bearing is obtained. W / m³.

[0032] Specifically, in step 3, the convective heat transfer coefficient The calculation process is as follows: First calculate the Reynolds number And Prandtl :

[0033] in, The average velocity of the fluid is m / s. The height of the convection gap (m). The fluid kinematic viscosity is (m² / s). Specific heat capacity of the fluid (J / (kg·℃)) The viscosity is the fluid dynamic viscosity (Pa·s). The fluid thermal conductivity is expressed in W / (m·℃). Then, choose the Nusselt number formula based on the magnitude of the Reynolds number:

[0034] Finally, the convective heat transfer coefficient is calculated based on the Nusselt number. :

[0035] in, The characteristic length (m) is determined based on the actual structure of the heat exchange surface. According to the actual assembly relationship of the B-axis power tool holder, the calculated convective heat transfer coefficient is assigned to the corresponding heat exchange surfaces, namely the electric spindle stator-rotor gap surface, the inner wall of the cooling water jacket, and the outer surface of the tool holder housing, to complete the setting of the heat exchange boundary conditions.

[0036] Specifically, in step 6, the milling force is calculated or measured experimentally based on actual machining parameters, the gravity load is applied in the form of gravitational acceleration of 9.8 m / s², and the fixed constraint restricts all degrees of freedom of the mounting surface.

[0037] Specifically, in step 8, when the rate of change of deformation after the mechanical load is superimposed is less than 1%, it is determined that the influence of the mechanical load on thermal deformation is negligible.

[0038] Those skilled in the art can adjust the heat generation rate calculation parameters, convective heat transfer coefficient and milling force values ​​of each heat source according to the specific B-axis power tool holder model and specifications. The above embodiments are only specific application examples and do not constitute a limitation on the scope of protection of the present invention.

[0039] Although embodiments of the invention have been shown and described, those skilled in the art will be able to make various changes, modifications, substitutions and alterations to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A thermo-mechanical coupling simulation analysis method for a B-axis power tool post, characterized in that, Includes the following steps: Step 1: Construct and simplify the 3D geometric model of the tool holder. Based on the actual structure of the B-axis power tool holder, a three-dimensional geometric model including the electric spindle, torque motor, housing, and cooling water jacket was established; threaded holes, bolt holes, chamfers, fillets, and non-load-bearing lines were deleted to simplify the model. Step 2: Determine the type of heat source and the heat generation rate The main heat sources of the tool post are identified as the electric spindle stator, electric spindle rotor, electric spindle front bearing, electric spindle rear bearing, B-axis torque motor stator, and B-axis torque motor rotor; a unified formula is used to calculate the heat generation rate of each heat source. Step 3: Set heat transfer boundary conditions The forced convection heat transfer inside the tool holder and the natural convection heat transfer outside were clearly defined; the convective heat transfer coefficient was calculated using the Nusselt number correlation method. and assign corresponding heat exchange surfaces; Step 4: Establish a thermo-mechanical coupled finite element model The simplified geometric model is imported into the finite element software, the material properties of each component are defined, the mesh is automatically generated, and the heat source area, bearing area, and tool tip are locally refined. Step 5: Apply thermal load and solve for the temperature field. Using the heat generation rate as a volume heat source and the convective heat transfer coefficient as a surface load, steady-state or transient thermal analysis is performed to obtain the overall temperature field of the tool holder. Step 6: Apply mechanical loads and constraints The temperature field is mapped as a thermal load onto the tool holder structure model, while milling force and gravity load are applied, and fixed constraints are applied to the tool holder mounting surface. Step 7: Solve for the thermo-mechanical coupled deformation field In the finite element analysis software, a thermo-structural coupling analysis was performed to solve the comprehensive deformation field of the B-axis dynamic tool holder under the combined action of thermal and mechanical loads. After the analysis was completed, the displacement fields of each key part of the tool holder in the X, Y, and Z directions were extracted to identify the location and amount of maximum deformation of the tool holder structure and to clarify the deformation distribution law in each direction. Step 8: Comparative Analysis Set up working conditions with only thermal load and working conditions with thermal load, milling force and gravity load, compare the difference in the deformation of the tool holder structure under the two working conditions, calculate the rate of change of deformation, and determine whether the influence of mechanical load on the thermal deformation of the tool holder is negligible.

2. The thermo-mechanical coupling simulation analysis method for a B-axis power tool post according to claim 1, characterized in that: In step 2, the heat generation rates of the electric spindle stator, electric spindle rotor, torque motor stator, and torque motor rotor are determined by... calculate; in, ΔP P1 represents the power loss of the heat source, and P2 represents the rated power of the heat source component. η For the working efficiency of the heat source components. The heat generation rate of the heat source. The volume of the heat source component; The bearing heat generation rate is calculated based on the friction torque calculation formula and obtained through conversion 3. The thermo-mechanical coupling simulation analysis method for a B-axis power tool post according to claim 2, characterized in that, The specific formula for calculating the frictional torque is as follows: ； in, The total frictional torque of the bearing. For bearing lubrication-related torques, For the load-related torque of the bearing, The bearing lubrication friction coefficient, The bearing's rotational speed. The average diameter of the bearing. The bearing load friction coefficient, This refers to the radial load on the bearing; The heat generation rate of the bearing is calculated from the total frictional torque, and combined with the bearing volume, the final heat generation rate of the bearing is obtained.

4. The thermo-mechanical coupling simulation analysis method for a B-axis power tool post according to claim 1, characterized in that, In step 3, the convective heat transfer coefficient The calculation process is as follows: First calculate the Reynolds number And Prandtl : in, The average velocity of the fluid. The height of the convection gap. For fluid kinematic viscosity, Specific heat capacity of the fluid For fluid dynamic viscosity, Thermal conductivity of the fluid; Then, choose the Nusselt number formula based on the magnitude of the Reynolds number: Finally, the convective heat transfer coefficient is calculated based on the Nusselt number. : in, The characteristic length is determined based on the actual structure of the heat exchange surface; Based on the actual assembly relationship of the B-axis power tool post, the calculated convective heat transfer coefficients are assigned to the corresponding heat transfer surfaces to complete the setting of heat transfer boundary conditions.

5. The thermo-mechanical coupling simulation analysis method for a B-axis power tool post according to claim 1, characterized in that: In step 4, the mesh type is selected as tetrahedral or hexahedral mesh, and the mesh distortion rate is ≤5%.

6. The thermo-mechanical coupling simulation analysis method for a B-axis power tool post according to claim 1, characterized in that, Step 5 specifically involves: The heat generation rate of each heat source is applied as a volume heat source to the corresponding heat source component. The calculated convective heat transfer coefficient is applied to the corresponding heat transfer surface. At the same time, the ambient temperature is set to the actual working ambient temperature of the tool holder. The heat conduction relationship between each component is defined, where the contact surface is set as thermal coupling and the gap surface is set as thermal resistance. Subsequently, steady-state or transient thermal analysis was performed to obtain the overall temperature field distribution cloud map of the B-axis power tool post, clarifying the temperature distribution pattern and the location of the highest temperature in each part.

7. The thermo-mechanical coupling simulation analysis method for a B-axis power tool post according to claim 1, characterized in that: In step 6, the milling force is calculated or measured experimentally based on actual machining parameters, the gravity load is applied in the form of gravitational acceleration of 9.8 m / s², and the fixed constraint restricts all degrees of freedom of the mounting surface.

8. The thermo-mechanical coupling simulation analysis method for a B-axis power tool post according to claim 1, characterized in that: In step 8, when the rate of change of deformation after the mechanical load is superimposed is less than 1%, it is determined that the influence of the mechanical load on thermal deformation is negligible.

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