Hollow honing spindle thermal characteristic multi-field coupling analysis and heat dissipation structure optimization method

Abstract

The application discloses a hollow honing spindle thermal characteristic multi-field coupling analysis and heat dissipation structure optimization method and belongs to the technical field of machine tool spindle cooling and heat dissipation. In view of the problem that the existing method is difficult to adapt to a large-diameter hollow honing spindle, a three-dimensional model of the hollow honing spindle is constructed, fluid and solid calculation domains are divided, and a thermal-flow coupling simulation is solved by flow-solid conjugate coupling to obtain a steady-state temperature field. Then, the temperature field is taken as a thermal load to perform thermal-solid coupling simulation to obtain a steady-state thermal deformation field. The heat exchange characteristic and pressure drop characteristic are obtained from the steady-state temperature field and the steady-state thermal deformation field of the optimized heat dissipation structure model. The optimal heat dissipation structure of the hollow honing spindle is selected according to the heat exchange characteristic and the pressure drop characteristic. The application solves the problem that the traditional thermal analysis method is difficult to adapt to a large hollow structure and optimizes the spindle heat dissipation structure and related parameters to reduce the spindle temperature rise and thermal deformation, improve the thermal stability, machining precision and operation reliability of the honing spindle.

Description

Technical Field

[0001] This application relates to the field of machine tool spindle cooling and heat dissipation, and more specifically, to a method for multi-field coupling analysis of the thermal characteristics of a hollow honing spindle and optimization of its heat dissipation structure. Background Technology

[0002] Internal meshing high-strength honing is an essential process for high-speed, low-noise gear precision machining. Its principle involves forced internal meshing between a honing wheel, shaped like an internal gear and mounted on the honing spindle, and a workpiece gear mounted on the workpiece spindle. The relative sliding of these two gears achieves minute material removal from the tooth surface. During this machining process, the honing spindle, as the core component driving the rotation of the honing wheel and bearing the machining load, directly affects the tooth profile error, tooth direction error, tooth surface roughness, and transmission noise level of the machined gear due to its rotational accuracy, rigidity, thermal stability, and dynamic performance.

[0003] The spindle, as the driving component in the machining process, is one of the main heat sources of CNC machine tools. Traditional spindles are mostly used in conventional rotary machining scenarios such as milling, grinding, and drilling. Their structure is usually a slender cylindrical or stepped cylindrical coaxial rotating structure. The central through hole of this type of electric spindle is usually small, mainly bearing the machining load from the end face. However, honing spindles for internal meshing high-strength gear honing often need to form a large-diameter hollow channel inside to meet the installation requirements of the honing wheel and the workpiece gear. Moreover, due to the use of internal meshing, the machining load is mostly applied inside the spindle, resulting in significant differences in its radial dimensions, wall thickness distribution, heat conduction path, thermal stability requirements, and fluid-structure interaction boundary conditions compared to traditional spindles. Traditional methods hardly consider the large-diameter hollow structure, machining heat conduction, and cooling medium flow of honing spindles. Therefore, the thermal characteristic analysis and optimization methods of traditional spindles are difficult to directly apply to large-diameter hollow honing spindles.

[0004] Therefore, it is necessary to propose a multi-field coupling analysis method for the thermal characteristics of hollow honing spindles and an optimal method for heat dissipation structure. This method comprehensively considers factors such as the characteristics of the large-diameter hollow structure of the honing spindle, electromagnetic heating of the spindle, frictional heating of the bearings, heat transfer from the flow of the cooling medium, structural stress, and thermal deformation. A multi-field coupling analysis model that conforms to the working conditions of internal meshing high-strength honing is established, and the heat dissipation structure and related parameters of the spindle are optimized to reduce the spindle temperature rise and thermal deformation, and improve the thermal stability, machining accuracy, and operational reliability of the honing spindle. Summary of the Invention

[0005] The purpose of this invention is to provide a method for multi-field coupling analysis of the thermal characteristics of a hollow honing spindle and optimization of its heat dissipation structure, which can meet the requirements for thermal characteristic mechanism analysis and modeling of the honing spindle and heat dissipation structure design, and provide a foundation for stable mass production of internal meshing high-strength honing gears.

[0006] This invention provides a method for multi-field coupling analysis of the thermal characteristics of a hollow honing spindle and optimization of its heat dissipation structure, including: Step S1: Construct a three-dimensional model based on the geometric structure of the hollow honing spindle; Step S2: Construct the fluid computation domain and solid computation domain of the three-dimensional model to form a simulation computation model. Perform parametric meshing on the simulation computation model and refine the local mesh in key areas to obtain the hollow honing spindle mesh. Step S3: Construct the fluid-solid conjugate coupling surface of the hollow honing spindle, use the fluid-solid conjugate coupling surface as the heat transfer boundary, perform heat-fluid coupling simulation based on the mesh of the hollow honing spindle, and solve for the steady-state temperature field; Step S4: Configure the contact pairs between the components of the hollow honing spindle to obtain the structural simulation model. Apply the steady-state temperature field as a thermal load to the structural simulation model and perform a thermo-solid coupling simulation on the structural simulation model to obtain the steady-state thermal deformation field. Step S5: Extract heat transfer characteristics and pressure drop characteristics from the steady-state temperature field and steady-state thermal deformation field; Step S6: Obtain the preferred heat dissipation structure model that meets the constraints. Obtain the heat transfer characteristics and pressure drop characteristics of each preferred heat dissipation structure model through steps S1 to S5. Determine the optimal heat dissipation structure model of the hollow honing spindle based on the obtained heat transfer characteristics and pressure drop characteristics.

[0007] In one optional embodiment, the geometry of the honing spindle includes a spindle, a stator, a rotor, front and rear bearings, a cooling water jacket, a spindle housing, and a receiving plate.

[0008] In one optional implementation, step S2 specifically includes: The 3D model is preprocessed and inspected and its surface is repaired. Solid regions of the spindle, stator, rotor, front and rear bearings, cooling water jacket, and spindle housing are extracted to form a solid computational domain. Extract the cooling medium region within the heat dissipation jacket to form a fluid computing domain, which includes the cooling fluid of the cooling structure and the spindle housing; A simulation model is formed based on the solid computing domain and the fluid computing domain, and the boundary conditions of the walls and the contact surfaces between the solid parts in the simulation model are configured. The wall surface includes the contact surface between each plate and the environment, the rotor rotating end face, the main shaft rotating end face, the inner surface of the stator, the outer surface of the rotor, and the contact surface between the bearing and compressed air; Parametric meshing was performed on the configured simulation model. Mesh size was refined for key areas including the main shaft, stator, rotor, front and rear bearings and cooling structure, and an expanded layer mesh was applied to the wall surface. Perform orthogonality verification on the completed mesh, and remove meshes whose orthogonality does not meet the preset simulation convergence threshold to obtain the hollow honing spindle mesh.

[0009] In one optional implementation, step S3 specifically includes: The heat generation rates of the bearings, stator, and rotor before and after the simulation are calculated as the first simulation boundary condition, and the convective heat transfer coefficients of the main convective heat transfer surfaces are calculated as the second simulation boundary condition. The main convection heat exchange surfaces include the rotor rotating end face, the main shaft rotating end face, the air gap between the stator and the rotor, the bearing and compressed air contact surface, the heat dissipation water jacket and the forced convection heat exchange surface of the cooling water, and the heat exchange surface between the shell and the surrounding environment. Set the cooling water inlet velocity, temperature, and wall properties as the third simulation boundary conditions; By setting up coupling interfaces based on the contact surfaces between each solid part, fluid-solid conjugate heat transfer and solid-solid heat conduction are realized, forming the fluid-solid conjugate coupling surface of the hollow honing spindle; Configure material properties, including density, specific heat capacity, and thermal conductivity, for the fluid computing domain and the solid computing domain respectively; The fluid computational domain and the solid computational domain are connected by a fluid-solid conjugate coupling surface. The first and second simulation boundary conditions are applied to the solid computational domain, and the third simulation boundary condition is applied to the fluid computational domain. The thermal-fluid coupling simulation is performed based on the hollow honed spindle mesh.

[0010] In one optional implementation, thermal-fluid coupling simulation is performed, specifically including: Solving the continuity equation, momentum equation, energy equation, and other equations using a pressure-velocity coupling algorithm. The turbulence model is used until the residuals meet the preset convergence conditions to obtain the steady-state temperature field; The continuity equation satisfies the following formula:

[0011] In the formula, It is a dimensionless gradient operator. The velocity is a dimensionless fluid velocity. The momentum equation satisfies the following formula:

[0012] In the formula, For fluid density, For the fluid velocity tensor, For time, For the Hamiltonian gradient operator, For hydrostatic pressure, For fluid viscosity, For temperature, For unit tensors, For mass force; The energy equation satisfies the following formula:

[0013] In the formula, For total enthalpy, The pressure on a fluid element. Thermal conductivity, The work done by viscous forces. As an internal heat source; The The turbulence model satisfies the following formula:

[0014] In the formula, The turbulent kinetic energy per unit mass of fluid. and For the orthogonal coordinate components in three-dimensional space, where , This is a spatial direction index, with values ​​of 1, 2, and 3, corresponding to the x, y, and z coordinate axes in three-dimensional space. For fluid flow velocity at Components of coordinate direction, The molecular dynamic viscosity of the fluid. and They are respectively equations and Prandtl's constant of the equation, The turbulent kinetic energy generated by the velocity gradient The turbulent kinetic energy generated by buoyancy, The turbulent kinetic energy dissipation rate per unit mass of fluid. This represents the effect of fluid pulsating expansion on the total dissipation rate. and These are the empirical coefficients for the dissipation rate generation term and the dissipation rate decay term, respectively. This is the buoyancy correction factor. This is a dissipation rate correction term.

[0015] In one alternative implementation, the heat transfer control equation between the solid computational domain and the fluid computational domain in the fluid-solid conjugate coupling surface satisfies the following formula:

[0016] In the formula, The thermal conductivity of a solid. For the Laplace operator, For thermal power, For fluid density, The specific heat capacity at constant pressure of the fluid. For convection terms, For fluid velocity, denoted as , where is the thermal conductivity of the fluid.

[0017] In one optional implementation, step S4 specifically includes: The structural simulation model is constructed by obtaining contact pairs including the binding contact of bolted connections between parts inside the spindle, the interference fit contact between the stator and the water jacket, the interference fit contact between the spindle and the inner ring of the bearing, and the interference fit contact between the spindle and the rotor. The steady-state temperature field is applied as a thermal load to the corresponding nodes in the structural simulation model, and the following constraints are set for the structural simulation model: A constant rotational speed load is applied to the rotating parts, the degree of freedom of the spindle housing end face is fixed, and radial support constraints are applied to the front and rear bearings. Thermo-solid coupled simulation is performed based on the constrained structural simulation model. A direct solver is used for steady-state solution, and the output is a steady-state thermal deformation field that includes total thermal deformation, axial thermal elongation, and radial thermal deformation.

[0018] In one optional embodiment, the heat exchange characteristics include the highest temperature of the heat dissipation jacket, the highest temperature of the stator, the highest temperature of the spindle, and the average convective heat transfer coefficient between the heat dissipation jacket and the cooling water. The pressure drop characteristic includes the pressure difference between the inlet and outlet of the cooling channel of the heat dissipation water jacket.

[0019] In an optional implementation, the constraint conditions in step S6 specifically include: Using a conventional rectangular cross-section spiral heat dissipation structure as the benchmark structure, the axial cooling coverage area, hydraulic diameter, and total flow channel length of each preferred heat dissipation structure must be consistent with the benchmark structure. And the flow channel arrangement satisfies the following formula:

[0020] In the formula, The distance between the centerlines of two adjacent flow channels. The minimum wall thickness between two adjacent flow channels. The length of the rectangular cross-section of the flow channel. The number of flow channels in the heat dissipation structure. The diameter is the center diameter of the flow channel.

[0021] This application has at least the following advantages or beneficial effects: Based on the spindle heat transfer characteristics, pressure drop characteristics, and thermal deformation field distribution characteristics, this invention optimizes the selection of the heat dissipation structure. It can determine the optimal heat dissipation structure while reducing spindle temperature rise, minimizing thermal deformation, controlling pressure drop, and ensuring structural manufacturability, thereby improving the thermal stability, rotational accuracy, and operational reliability of large-diameter hollow honing spindles. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of the method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle provided by the present invention; Figure 2 This is a schematic diagram of a three-dimensional model of the hollow honing spindle in an embodiment of the present invention; Figure 3 This is a schematic diagram of a conventional rectangular cross-section spiral heat dissipation structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the hollow honing spindle grid in an embodiment of the present invention; Figure 5 This is a steady-state temperature field distribution diagram in an embodiment of the present invention; Figure 6 This is a steady-state thermal deformation field distribution diagram in an embodiment of the present invention; Figure 7 The following are simulation results of the spiral heat dissipation structure in the embodiment of the present invention, wherein (a) is the temperature distribution diagram of the spiral heat dissipation structure and (b) is the pressure drop distribution diagram of the spiral heat dissipation structure. Figure 8 This is a schematic diagram of a preferred heat dissipation structure in an embodiment of the present invention, wherein part (a) is a schematic diagram of a serpentine heat dissipation structure and part (b) is a schematic diagram of a series-parallel heat dissipation structure; Figure 9 The following are thermal deformation field distribution diagrams of the simulation results in the embodiments of the present invention, wherein (a) is the thermal deformation field distribution diagram of the honing spindle under the serpentine heat dissipation structure, and (b) is the thermal deformation field distribution diagram of the honing spindle under the series-parallel heat dissipation structure. Figure 10 The following are simulation results of the serpentine heat dissipation structure in the embodiment of the present invention, wherein (a) is a temperature distribution diagram of the serpentine heat dissipation structure and (b) is a pressure drop distribution diagram of the serpentine heat dissipation structure. Figure 11 The following are simulation results of the series-parallel heat dissipation structure in the embodiment of the present invention, wherein (a) is a temperature distribution diagram of the series-parallel heat dissipation structure and (b) is a voltage drop distribution diagram of the series-parallel heat dissipation structure. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] Please refer to Figure 1 , Figure 1 This is a flowchart of the multi-field coupling analysis of the thermal characteristics of the hollow honing spindle and the optimization method of the heat dissipation structure proposed in this application, including: Step S1: Construct a three-dimensional model based on the geometric structure of the hollow honing spindle; In one embodiment, the geometry of the honing spindle includes a spindle, a stator, a rotor, front and rear bearings, a cooling water jacket, a spindle housing, and a receiving plate.

[0026] In this embodiment, as shown Figure 2 The honing spindle of a certain model shown is the object of study, and the reference numerals in the attached figures are as follows: 1-Housing, 2-First receiving plate, 3-First ring, 4-Front bearing, 5-Main shaft, 6-Second receiving plate, 7-Rotor, 8-Stator, 9-Cooling water jacket, 10-Bearing sleeve, 11-Rear bearing, 12-Adjusting washer, 13-Second ring, 14-Pressure cap, 15-Third receiving plate, 16-Fourth receiving plate.

[0027] In this embodiment, the following is adopted: Figure 3 The geometric parameters of the conventional rectangular cross-section spiral heat dissipation structure shown are shown in Table 1: Table 1 Geometric parameters of the spiral heat dissipation structure

[0028] In this embodiment, the geometry of the hollow honing spindle is established based on the actual geometry and dimensional parameters of the large-diameter hollow honing spindle for internal meshing high-strength honing, and by simplifying features such as threaded holes and chamfers.

[0029] Further analysis of the main heat sources and heat generation mechanism of the hollow honing spindle is as follows: Internal meshing high-strength honing is a micro-grinding process. Due to the presence of cooling oil in the honing area, there is almost no excess heat conducted to the spindle. Therefore, the main heat sources of the hollow honing spindle include a large-diameter frameless torque motor and a large-diameter thin-walled bearing. The heat generation of a large-diameter frameless torque motor satisfies the following formula:

[0030] In the formula, and These are the rotor heat generation rate and the stator heat generation rate, respectively. To reduce power loss, and These are the stator volume and the rotor volume, respectively. The heat generation mechanism of large-diameter thin-walled bearings satisfies the following formula:

[0031] In the formula, , and These are the heat flux densities of the bearing inner ring, outer ring, and rolling elements, respectively. The heat generation power of the bearing, , , These are the surface areas of the bearing's inner raceway, outer raceway, and rolling elements, respectively. The formula for calculating heat generation power is as follows:

[0032]

[0033] in,

[0034] In the formula, For bearing speed, This represents the total frictional torque of the bearing. This refers to the frictional torque between the rolling elements and raceways of the bearing. This refers to the frictional torque between the rolling elements of the bearing and the lubricating oil. The average diameter of the bearing. A coefficient related to bearing type and lubrication method. The kinematic viscosity of the lubricating oil. This is a coefficient related to the bearing type and the load it is subjected to. This is a coefficient related to the magnitude and direction of the force.

[0035] Step S2: Construct the fluid computation domain and solid computation domain of the three-dimensional model to form a simulation computation model. Perform parametric meshing on the simulation computation model and refine the local mesh in key areas to obtain the hollow honing spindle mesh. In one embodiment, step S2 specifically includes: The 3D model is preprocessed and inspected and its surface is repaired. Solid regions of the spindle, stator, rotor, front and rear bearings, cooling water jacket, and spindle housing are extracted to form a solid computational domain. Extract the cooling medium region within the heat dissipation jacket to form a fluid computing domain, which includes the cooling fluid of the cooling structure and the spindle housing; A simulation model is formed based on the solid computing domain and the fluid computing domain, and the boundary conditions of the walls and the contact surfaces between the solid parts in the simulation model are configured. The wall surface includes the contact surface between each plate and the environment, the rotor rotating end face, the main shaft rotating end face, the inner surface of the stator, the outer surface of the rotor, and the contact surface between the bearing and compressed air; Parametric meshing was performed on the configured simulation model. Mesh size was refined for key areas including the main shaft, stator, rotor, front and rear bearings and cooling structure, and an expanded layer mesh was applied to the wall surface. Perform orthogonality verification on the completed mesh, and remove meshes whose orthogonality does not meet the preset simulation convergence threshold to obtain the hollow honing spindle mesh.

[0036] Preferably, volume extraction or Boolean operations can be used to create the fluid computational domain.

[0037] Preferably, parametric mesh generation can employ tetrahedral patch adaptive meshing and automatic meshing.

[0038] In this embodiment, the three-dimensional model is processed based on step S2 to obtain the following result: Figure 4 The hollow honing spindle grid shown.

[0039] Step S3: Construct the fluid-solid conjugate coupling surface of the hollow honing spindle, use the fluid-solid conjugate coupling surface as the heat transfer boundary, perform heat-fluid coupling simulation based on the mesh of the hollow honing spindle, and solve for the steady-state temperature field; In one embodiment, step S3 specifically includes: The heat generation rates of the bearings, stator, and rotor before and after the simulation are calculated as the first simulation boundary condition, and the convective heat transfer coefficients of the main convective heat transfer surfaces are calculated as the second simulation boundary condition. The main convection heat exchange surfaces include the rotor rotating end face, the main shaft rotating end face, the air gap between the stator and the rotor, the bearing and compressed air contact surface, the heat dissipation water jacket and the forced convection heat exchange surface of the cooling water, and the heat exchange surface between the shell and the surrounding environment. Set the cooling water inlet velocity, temperature, and wall properties as the third simulation boundary conditions; By setting up coupling interfaces based on the contact surfaces between each solid part, fluid-solid conjugate heat transfer and solid-solid heat conduction are realized, forming the fluid-solid conjugate coupling surface of the hollow honing spindle; Configure material properties, including density, specific heat capacity, and thermal conductivity, for the fluid computing domain and the solid computing domain respectively; The fluid computational domain and the solid computational domain are connected by a fluid-solid conjugate coupling surface. The first and second simulation boundary conditions are applied to the solid computational domain, and the third simulation boundary condition is applied to the fluid computational domain. The thermal-fluid coupling simulation is performed based on the hollow honed spindle mesh.

[0040] The thermal-fluid coupling simulation includes: Solving the continuity equation, momentum equation, energy equation, and other equations using a pressure-velocity coupling algorithm. The turbulence model is used until the residuals meet the preset convergence conditions to obtain the steady-state temperature field; The continuity equation satisfies the following formula:

[0041] In the formula, It is a dimensionless gradient operator. The velocity is a dimensionless fluid velocity. The momentum equation satisfies the following formula:

[0042] In the formula, The instantaneous density of the fluid. For the fluid velocity tensor, For time, For the Hamiltonian gradient operator, For hydrostatic pressure, For fluid viscosity, For temperature, For unit tensors, For mass force; The energy equation satisfies the following formula:

[0043] In the formula, For total enthalpy, The pressure on a fluid element. Thermal conductivity, The work done by viscous forces. For fluid viscous stress tensor, As an internal heat source; The The turbulence model satisfies the following formula:

[0044] In the formula, The turbulent kinetic energy per unit mass of fluid. and For the orthogonal coordinate components in three-dimensional space, where , This is a spatial direction index, with values ​​of 1, 2, and 3, corresponding to the x, y, and z coordinate axes in three-dimensional space. For fluid flow velocity at Components of coordinate direction, The molecular dynamic viscosity of the fluid. and They are respectively equations and Prandtl's constant of the equation, The turbulent kinetic energy generated by the velocity gradient The turbulent kinetic energy generated by buoyancy, The turbulent kinetic energy dissipation rate per unit mass of fluid. This represents the effect of fluid pulsating expansion on the total dissipation rate. and These are the empirical coefficients for the dissipation rate generation term and the dissipation rate decay term, respectively. This is the buoyancy correction factor. This is a dissipation rate correction term.

[0045] The formula for calculating the forced convection heat transfer coefficient between the rotor's rotating end face and the air is as follows:

[0046] In the formula, The forced convection heat transfer coefficient between the rotor's rotating end face and the air. The average linear velocity of the rotor end face. For bearing speed, The average diameter at the rotor end; The formula for calculating the forced convection heat transfer coefficient between the rotating end face of the spindle and the air is:

[0047] In the formula, The forced convection heat transfer coefficient between the rotating end face of the main shaft and the air. The average speed at the spindle end; The formula for calculating the forced convection heat transfer coefficient of the air gap between the stator and rotor is:

[0048] In the formula, The forced convection heat transfer coefficient is the air gap between the stator and rotor. The thermal conductivity is the coefficient of the medium (usually air) filling the air gap. The radial gap width from the inner wall of the stator to the outer wall of the rotor; The formula for calculating the convective heat transfer coefficient between the bearing and compressed air is:

[0049] In the formula, The convective heat transfer coefficient between the bearing and the compressed air is denoted as . The average velocity of compressed air in the bearing. The airflow acting on the bearing. This represents the contact area between the bearing and the axial airflow. Main spindle rotational angular velocity, This is the average diameter of the inner and outer rings of the bearing. This represents the average clearance between the inner and outer rings of the bearing and the cage. The formula for calculating the heat transfer coefficient between the heat dissipation jacket and the forced convection of cooling water is as follows:

[0050] In the formula, The forced convection heat transfer coefficient between the heat dissipation jacket and the cooling water is... The Reynolds number is the number of cooling water flowing within the flow channel. The Prandtl number of the cooling water. The thermal conductivity of the cooling water. The hydraulic diameter of the cooling channel. and These are the length and width of the rectangular cross-section, respectively. The convective heat transfer coefficient between the shell and the surrounding environment is:

[0051] The heat transfer control equation between the solid computational domain and the fluid computational domain in the fluid-solid conjugate coupling surface satisfies the following formula:

[0052] In the formula, The thermal conductivity of a solid. For the Laplace operator, For thermal power, For fluid density, The specific heat capacity at constant pressure of the fluid. For convection terms, For fluid velocity, denoted as , where is the thermal conductivity of the fluid.

[0053] in, Turbulence models are used to simulate the turbulent motion of cooling water to achieve the purpose of cooling and heat dissipation.

[0054] In this embodiment, the heat generation rates of the front and rear bearings, stator, and rotor are specifically shown in Table 2: Table 2 Heat generation rate

[0055] The specific flow coefficients of the main convective heat transfer surfaces are shown in Table 3: Table 3 Convection heat transfer coefficients

[0056] In this embodiment, based on step S3, the following is obtained: Figure 5 The steady-state temperature field of the hollow honing spindle is shown.

[0057] Step S4: Configure the contact pairs between the components of the hollow honing spindle to obtain the structural simulation model. Apply the steady-state temperature field as a thermal load to the structural simulation model and perform a thermo-solid coupling simulation on the structural simulation model to obtain the steady-state thermal deformation field. In one embodiment, step S4 specifically includes: The structural simulation model is constructed by obtaining contact pairs including the binding contact of bolted connections between parts inside the spindle, the interference fit contact between the stator and the water jacket, the interference fit contact between the spindle and the inner ring of the bearing, and the interference fit contact between the spindle and the rotor. The steady-state temperature field is applied as a thermal load to the corresponding nodes in the structural simulation model, and the following constraints are set for the structural simulation model: A constant rotational speed load is applied to the rotating parts, the degree of freedom of the spindle housing end face is fixed, and radial support constraints are applied to the front and rear bearings. Thermo-solid coupled simulation is performed based on the constrained structural simulation model. A direct solver is used for steady-state solution, and the output is a steady-state thermal deformation field that includes total thermal deformation, axial thermal elongation, and radial thermal deformation.

[0058] In this embodiment, step S4 yields the following result: Figure 6 The diagram shows the steady-state thermal deformation field distribution.

[0059] Among them, axial thermal elongation changes the relative position of the honing wheel and the workpiece, thus affecting gear accuracy; radial thermal deformation reduces the return transmission accuracy and bearing radial clearance, and the decrease in return transmission accuracy and machining tooth profile accuracy, as well as the reduction in radial clearance, can cause bearing jamming or even overheating and damage.

[0060] Step S5: Extract heat transfer characteristics and pressure drop characteristics from the steady-state temperature field and steady-state thermal deformation field; In one embodiment, the heat transfer characteristics include the highest temperature of the heat dissipation water jacket, the highest temperature of the stator, the highest temperature of the spindle, and the average convective heat transfer coefficient between the heat dissipation water jacket and the cooling water. The pressure drop characteristic includes the pressure difference between the inlet and outlet of the cooling channel of the heat dissipation water jacket.

[0061] Among them, heat exchange characteristics can determine the heat exchange capacity of different heat dissipation water jackets, and pressure drop characteristics can determine the pressure drop potential energy of cooling water flowing through the water jacket and the energy consumption of the pump.

[0062] In this embodiment, the following is obtained: Figure 7 The diagram shows the temperature distribution and pressure drop distribution of the spiral heat dissipation structure.

[0063] Step S6: Obtain the preferred heat dissipation structure model that meets the constraints. Obtain the heat transfer characteristics and pressure drop characteristics of each preferred heat dissipation structure model through steps S1 to S5. Determine the optimal heat dissipation structure model of the hollow honing spindle based on the obtained heat transfer characteristics and pressure drop characteristics.

[0064] In one embodiment, the constraints described in step S6 specifically include: Using a conventional rectangular cross-section spiral heat dissipation structure as the benchmark structure, the axial cooling coverage area, hydraulic diameter, and total flow channel length of each preferred heat dissipation structure must be consistent with the benchmark structure. And the flow channel arrangement satisfies the following formula:

[0065] In the formula, The distance between the centerlines of two adjacent flow channels. The minimum wall thickness between two adjacent flow channels. The length of the rectangular cross-section of the flow channel. The number of flow channels in the heat dissipation structure. The diameter is the center diameter of the flow channel.

[0066] In this embodiment, the preferred heat dissipation structure is as follows: Figure 8 The serpentine heat dissipation structure and the series-parallel heat dissipation structure are shown; The formulas for calculating the flow channel lengths of the reference structure and the preferred heat dissipation structure are as follows:

[0067] In the formula, , , These refer to the total flow channel lengths of the spiral heat dissipation structure, the serpentine heat dissipation structure, and the series-parallel heat dissipation structure, respectively. The outer diameter of the cooling structure, The number of spiral coils, The helix angle, , These refer to the number of flow channels in the serpentine heat dissipation structure and the series-parallel heat dissipation structure, respectively. For a single axial length, The distance between the centerlines of two adjacent flow channels. For pitch, The diameter is the center diameter of the flow channel.

[0068] In this embodiment, as Figure 9 , Figure 10 and Figure 11 The diagrams show the thermal deformation field distribution of the honing spindle, the temperature distribution of the heat dissipation structure, and the pressure drop distribution under each preferred heat dissipation structure.

[0069] Comparative analysis shows that the maximum steady-state temperature, steady-state water temperature, and maximum pressure drop of the series-parallel structure are the lowest among the three heat dissipation structures, which are 60.379℃, 39.76℃, and 3559.1Pa, respectively.

[0070] Therefore, in this embodiment, the heat exchange performance and pressure drop performance of the series-parallel structure cooling water jacket are both optimal, and it is adopted as the optimal heat dissipation structure model for the honing spindle in this embodiment.

[0071] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0072] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0073] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0074] The above provides a detailed description of the multi-field coupling analysis of the thermal characteristics of the hollow honing spindle and the optimization method for heat dissipation structure provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for multi-field coupled analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle, characterized in that, include: Step S1: Construct a three-dimensional model based on the geometric structure of the hollow honing spindle; Step S2: Construct the fluid computation domain and solid computation domain of the three-dimensional model to form a simulation computation model. Perform parametric meshing on the simulation computation model and refine the local mesh in key areas to obtain the hollow honing spindle mesh. Step S3: Construct the fluid-solid conjugate coupling surface of the hollow honing spindle, use the fluid-solid conjugate coupling surface as the heat transfer boundary, perform heat-fluid coupling simulation based on the mesh of the hollow honing spindle, and solve for the steady-state temperature field; Step S4: Configure the contact pairs between the components of the hollow honing spindle to obtain the structural simulation model. Apply the steady-state temperature field as a thermal load to the structural simulation model and perform a thermo-solid coupling simulation on the structural simulation model to obtain the steady-state thermal deformation field. Step S5: Extract heat transfer characteristics and pressure drop characteristics from the steady-state temperature field and steady-state thermal deformation field; Step S6: Obtain the preferred heat dissipation structure model that meets the constraints. Obtain the heat transfer characteristics and pressure drop characteristics of each preferred heat dissipation structure model through steps S1 to S5. Determine the optimal heat dissipation structure model of the hollow honing spindle based on the obtained heat transfer characteristics and pressure drop characteristics.

2. The method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle according to claim 1, characterized in that, The geometry of the honing spindle includes a spindle, stator, rotor, front and rear bearings, cooling water jacket, spindle housing, and receiving plate.

3. The method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle according to claim 1, characterized in that, Step S2 specifically includes: The 3D model is preprocessed and inspected and its surface is repaired. The solid regions of the spindle, stator, rotor, front and rear bearings, cooling water jacket, and spindle housing are extracted to form a solid computational domain. Extract the cooling medium region within the heat dissipation jacket to form a fluid computing domain, which includes the cooling fluid of the cooling structure and the spindle housing; A simulation model is formed based on the solid computing domain and the fluid computing domain, and the boundary conditions of the walls and the contact surfaces between the solid parts in the simulation model are configured. The wall surface includes the contact surface between each plate and the environment, the rotor rotating end face, the main shaft rotating end face, the inner surface of the stator, the outer surface of the rotor, and the contact surface between the bearing and compressed air; Parametric meshing was performed on the configured simulation model. Mesh size was refined for key areas including the main shaft, stator, rotor, front and rear bearings and cooling structure, and an expanded layer mesh was applied to the wall surface. Perform orthogonality verification on the completed mesh, and remove meshes whose orthogonality does not meet the preset simulation convergence threshold to obtain the hollow honing spindle mesh.

4. The method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle according to claim 1, characterized in that, Step S3 specifically includes: The heat generation rate of the bearings, stator, and rotor before and after the simulation is calculated as the first simulation boundary condition, and the convective heat transfer coefficient of the main convective heat transfer surface is calculated as the second simulation boundary condition. The main convection heat exchange surfaces include the rotor rotating end face, the main shaft rotating end face, the air gap between the stator and the rotor, the bearing and compressed air contact surface, the heat dissipation water jacket and the forced convection heat exchange surface of the cooling water, and the heat exchange surface between the shell and the surrounding environment. Set the cooling water inlet velocity, temperature, and wall properties as the third simulation boundary conditions; By setting up coupling interfaces based on the contact surfaces between each solid part, fluid-solid conjugate heat transfer and solid-solid heat conduction are realized, forming the fluid-solid conjugate coupling surface of the hollow honing spindle; Configure material properties, including density, specific heat capacity, and thermal conductivity, for the fluid computing domain and the solid computing domain respectively; The fluid computational domain and the solid computational domain are connected by a fluid-solid conjugate coupling surface. The first and second simulation boundary conditions are applied to the solid computational domain, and the third simulation boundary condition is applied to the fluid computational domain. The thermal-fluid coupling simulation is performed based on the hollow honed spindle mesh.

5. The method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle according to claim 4, characterized in that, Performing thermal-fluid coupling simulations specifically includes: Solving the continuity equation, momentum equation, energy equation, and other equations using a pressure-velocity coupling algorithm. The turbulence model is used until the residuals satisfy the preset convergence condition to obtain the steady-state temperature field; The continuity equation satisfies the following formula: In the formula, It is a dimensionless gradient operator. The velocity is a dimensionless fluid velocity. The momentum equation satisfies the following formula: In the formula, For fluid density, For the fluid velocity tensor, For time, For Hamiltonian operators, For hydrostatic pressure, For fluid viscosity, For temperature, For unit tensors, For mass force; The energy equation satisfies the following formula: In the formula, For total enthalpy, The pressure on a fluid element. Thermal conductivity, The work done by viscous forces. For fluid viscous stress tensor, As an internal heat source; The The turbulence model satisfies the following formula: In the formula, The turbulent kinetic energy per unit mass of fluid. and For the orthogonal coordinate components in three-dimensional space, where , This is a spatial direction index, with values ​​of 1, 2, and 3, corresponding to the x, y, and z coordinate axes in three-dimensional space. For fluid flow velocity at Components of coordinate direction, The molecular dynamic viscosity of the fluid. and They are respectively equations and Prandtl's constant of the equation, The turbulent kinetic energy generated by the velocity gradient The turbulent kinetic energy generated by buoyancy, The turbulent kinetic energy dissipation rate per unit mass of fluid. This represents the effect of fluid pulsating expansion on the total dissipation rate. and These are the empirical coefficients for the dissipation rate generation term and the dissipation rate decay term, respectively. This is the buoyancy correction factor. This is a dissipation rate correction term.

6. The method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle according to claim 4, characterized in that, The heat transfer governing equations between the solid and fluid computational domains in the fluid-solid conjugate coupling surface satisfy the following formula: In the formula, The thermal conductivity of a solid. For the Laplace operator, For thermal power, For fluid density, The specific heat capacity at constant pressure of the fluid. For convection terms, For fluid velocity, is the thermal conductivity of the fluid.

7. The method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle according to claim 1, characterized in that, Step S4 specifically includes: The structural simulation model is constructed by obtaining contact pairs including the bolted connections between parts inside the spindle, the interference fit contacts between the stator and the water jacket, the interference fit contacts between the spindle and the inner ring of the bearing, and the interference fit contacts between the spindle and the rotor. The steady-state temperature field is applied as a thermal load to the corresponding nodes in the structural simulation model, and the following constraints are set for the structural simulation model: A constant rotational speed load is applied to the rotating parts, the degree of freedom of the spindle housing end face is fixed, and radial support constraints are applied to the front and rear bearings. Thermo-solid coupled simulation is performed based on the constrained structural simulation model. A direct solver is used for steady-state solution, and the output is a steady-state thermal deformation field that includes total thermal deformation, axial thermal elongation, and radial thermal deformation.

8. The method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle according to claim 1, characterized in that, The heat transfer characteristics include the highest temperature of the heat dissipation water jacket, the highest temperature of the stator, the highest temperature of the spindle, and the average convective heat transfer coefficient between the heat dissipation water jacket and the cooling water. The pressure drop characteristic includes the pressure difference between the inlet and outlet of the cooling channel of the heat dissipation water jacket.

9. The method for multi-field coupling analysis of thermal characteristics and optimization of heat dissipation structure of hollow honing spindle according to claim 1, characterized in that, The constraints mentioned in step S6 specifically include: Using a conventional rectangular cross-section spiral heat dissipation structure as the benchmark structure, the axial cooling coverage area, hydraulic diameter, and total flow channel length of each preferred heat dissipation structure must be consistent with the benchmark structure. And the flow channel arrangement satisfies the following formula: In the formula, The distance between the centerlines of two adjacent flow channels. The minimum wall thickness between two adjacent flow channels. The length of the rectangular cross-section of the flow channel. The number of flow channels in the heat dissipation structure. The diameter is the center diameter of the flow channel.

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