A transmission system load-bearing interface modeling method, system and storage medium

Abstract

The present invention discloses a transmission system load-bearing interface modeling method, system and storage medium, and relates to the field of gear transmission technology. The method includes: establishing a three-dimensional model of the load-bearing interface, and meshing the fluid domain in the three-dimensional model of the load-bearing interface; determining the simulation working condition, using the VOF model to model the fluid domain of the load-bearing interface, and capturing the phase interface in the multiphase flow in the gear transmission; using the thermal network model to model the solid domain of the load-bearing interface, and discretizing the solid domain part into a number of temperature nodes; based on gear dynamics, calculating the friction heat generated by the gear pair, obtaining the heat source in the meshing state, and applying it to the thermal network model for simulation calculation; encapsulating the modeled load-bearing interface model into an analysis system, and calculating the heat source of the load-bearing interface through an integrated calculation method. Through the present invention, a reference can be provided for the research process of temperature changes and multiphase flow behaviors of transmission gears, and research efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gear transmission, and in particular to a transmission system load-bearing interface modeling method, system and storage medium. Background Art

[0002] The demand for high-speed, high-power density helical gear transmission in special vehicles, aerospace and offshore vessels is growing, and gear reducers with splash lubrication characteristics are one of the important transmission components to meet this trend. Good lubrication and thermal reliability are crucial to the efficiency and stability of gear reducers, so it is necessary to study the complex thermal-fluid coupling process inside gear reducers.

[0003] For transmission systems, the time scale of temperature diffusion is usually 102-105 times longer than that of multiphase flow. Most current numerical methods use equal time steps to solve the information of various physical fields in the fluid domain and the solid domain. Although the adaptive evolution of the temperature of the gear body can be achieved in principle, the huge time cost makes the study process of temperature changes and multiphase flow behavior inside the gear reducer difficult to achieve in practice.

[0004] Therefore, it is necessary to provide a multi-field coupling modeling method for transmission systems based on cross-time scales to solve the above problems. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a transmission system load-bearing interface modeling method, system and storage medium.

[0006] According to one aspect of the present invention, a transmission system load-bearing interface modeling method is provided, comprising:

[0007] Establishing a three-dimensional model of a load-bearing interface, wherein the load-bearing interface is a meshing gear pair, and meshing a fluid domain in the three-dimensional model of the load-bearing interface;

[0008] Determine the simulation conditions, use the VOF model to model the fluid domain of the load-bearing interface, and capture the phase interface in the multiphase flow in the gear transmission;

[0009] The solid domain of the load-bearing interface is modeled using a thermal network model, and the solid domain is partially discretized into several temperature nodes;

[0010] Based on gear dynamics, calculate the friction heat generated by the gear pair, obtain the heat source in the meshing state, and apply it to the thermal network model for simulation calculation;

[0011] The modeled load-bearing interface model is encapsulated into an analysis system, in which the input parameters are the working condition data of the gear pair, and the output parameters are the oil stirring power loss and temperature change of the gear pair.

[0012] Furthermore, the meshing of the fluid domain in the three-dimensional model of the load-bearing interface includes:

[0013] Divide the load-bearing interface into a driving wheel area, a driven wheel area and a gear box area;

[0014] The driving wheel area and the driven wheel area are set in the foreground grid, and the box area is used as the background grid, wherein the foreground grid unit is a mixed hexahedral grid and the background grid unit is a structured hexahedral grid;

[0015] An overlapping interface is established between the driving wheel area and the box area, and between the driven wheel area and the box area, and the overlapping interface is used to realize the transmission of information between the driving wheel area and the box area, and between the driven wheel area and the box area;

[0016] A dilation layer is set between the background mesh and the foreground mesh walls to ensure normalized wall distance.

[0017] Furthermore, the simulation working conditions include oil immersion depth, gear speed, and lubricating oil temperature, and the modeling of the fluid domain of the load-bearing interface using the VOF model includes:

[0018] The VOF model is used to perform multiphase thermal-fluid coupling on the heat transfer and flow in the fluid domain of the load-bearing interface model through the following control equations:

[0019] Continuity equation:

[0020] ;

[0021] In the formula, ρ is the fluid density, t It's time. is the velocity vector of the fluid;

[0022] Momentum equation:

[0023] ;

[0024] ;

[0025] In the formula, P It's pressure. μ is the dynamic viscosity, is the acceleration due to gravity, is the surface tension, is the surface tension coefficient, is the air volume fraction, is the air density, is the curvature of the air interface, is the air volume fraction, is the lubricating oil volume fraction, is the density of the lubricating oil, is the curvature of the lubricating oil interface, is the lubricating oil volume fraction;

[0026] Energy equation:

[0027] ;

[0028] In the formula, It's energy. is the effective thermal conductivity, T is the temperature, is the energy source term;

[0029] The energy lost in churning is S E The form of is applied to the fluid domain, and the formula is as follows:

[0030] ;

[0031] In the formula, M P , M P,axle They represent the oil stirring torque of the driving gear and the oil stirring torque of the driving gear shaft respectively. M G , M G,axle They represent the oil stirring torque of the driven gear and the oil stirring torque of the driven gear shaft respectively, , Respectively represent the speed of the driving gear and the speed of the driven gear, V l is the total lubricating oil volume;

[0032] The VOF model is used to predict the distribution of each phase and the mixture density within each grid unit. ρ and viscosity μ for:

[0033] ;

[0034] ;

[0035] ;

[0036] In the formula, represents the viscosity of air, Indicates the viscosity of the lubricating oil;

[0037] when =1, it means that the grid cell is full of air, and when =0, it means there is no lubricating oil in the grid unit.

[0038] Furthermore, the thermal network model is used to model the solid domain of the load-bearing interface, and the solid domain is partially discretized into a number of temperature nodes, including:

[0039] The driving gear, driving gear shaft, driven gear, and driven gear shaft are discretized into 6, 14, 12, and 13 temperature nodes respectively;

[0040] For each temperature node TN , the following energy equation needs to be satisfied:

[0041] ;

[0042] In the formula, Q ij To connect the temperature node TN j and temperature nodes TN i The heat exchange between S i To join TN i The heat source, ρ i , V i , C Pi , T TN,i They are TN i density, volume, specific heat capacity, temperature, n is the number of temperature nodes;

[0043] Based on the energy equation, each temperature node of the gear pair is established TN The transient iterative energy expression of is:

[0044] Heat transfer at the tooth tip node:

[0045] ;

[0046] In the formula, T ave,fluid is the average temperature of the fluid, T TN,1 is the temperature node at the tooth top, T TN,2 is the temperature node of the gear body near the outer side and adjacent to the tooth top, S To join T TN,1 The heat source, is the temperature node of the tooth top at time t+1, Δ t represents the solid domain iteration time step, R c is the convective heat transfer thermal resistance,R d,gear is the thermal resistance between nodes on the gear body;

[0047] Heat transfer from the gear body node along the radius of the gear:

[0048] ;

[0049] T TN,3 For T TN,2 Adjacent temperature nodes, It is the temperature node of the gear body near the outer side and adjacent to the tooth top at time t+1;

[0050] Heat transfer at nodes between gears and gear shafts:

[0051] ;

[0052] T TN,m-1 is the temperature node in the gear body close to the shaft, T TN,m is the temperature node between the gear body and the shaft, T TN,m+1 is the temperature node on the shaft close to the gear body, R d,axle is the thermal resistance between nodes on the gear shaft, is the temperature node between the gear body and the shaft at time t+1;

[0053] Heat transfer at nodes on gear shaft:

[0054] ;

[0055] T TN,m+2 On axis and T TN,m+1 Adjacent temperature nodes, It is the temperature node on the axis close to the gear body at time t+1;

[0056] Heat transfer at gear shaft end node:

[0057] ;

[0058] T TN,m+n is the temperature node of the shaft end surface, T TN,m+n-1 On axis and T TN,m+n Adjacent temperature nodes, is the temperature node of the shaft end surface at time t+1;

[0059] According to heat transfer theory, the thermal resistance between nodes on the gear body is for:

[0060] ;

[0061] Farther from the axis TN radius, Closer to the axis TN radius, is the thermal conductivity, B is the tooth width;

[0062] Thermal resistance between nodes on the gear shaft for:

[0063] ;

[0064] l is the temperature node spacing, A is the heat exchange area;

[0065] Convective heat transfer resistance for:

[0066] ;

[0067] are the temperature nodes on the gear and shaft, Q is the convective heat transfer at the wall of the corresponding area in the fluid domain.

[0068] Furthermore, the calculation of frictional heat generated by the gear pair based on gear dynamics, obtaining the heat source in the meshing state, and applying it to the thermal network model for simulation calculation includes:

[0069] Establishing a coordinate system based on gear dynamics, and solving the positions of each meshing point of the gear pair during the meshing process based on the coordinate system;

[0070] For each meshing point on each meshing line, the sliding loss and rolling loss are calculated using empirical equations;

[0071] Use the heat distribution coefficient to determine the heat source of the driving gear and the driven gear at each meshing point;

[0072] According to the heat sources of the driving gear and the driven gear at each meshing point, the average heat source of each meshing line is calculated;

[0073] The weighted average is taken according to the length of each meshing line to obtain the heat source in the current meshing state;

[0074] The heat sources of all calculation cycles in the transmission process are averaged to obtain the average heat source in the transmission process;

[0075] The calculated heat source data are applied to the solid domain thermal network model.

[0076] Furthermore, for each meshing point on each meshing line, calculating the sliding loss and rolling loss using an empirical equation includes:

[0077] Calculate the integrated radius of curvature at the meshing point R CC :

[0078] ;

[0079] In the formula, R C,P It represents the radius of curvature of the driving gear at the meshing point. R C,G It represents the radius of curvature of the driven gear at the meshing point;

[0080] The sliding speed is:

[0081] ;

[0082] ;

[0083] In the formula, V S,P is the sliding speed of the driving gear, V S,G is the sliding speed of the driven gear, is the speed of the driving gear, is the speed of the driven gear;

[0084] Relative sliding speed V RS and scroll speed V RR for:

[0085] ;

[0086] ;

[0087] Relative slip ratio V SR for:

[0088] ;

[0089] Maximum Hertzian contact stress σ max for:

[0090] ;

[0091] In the formula, F nis the normal force, L C is the contact line length at the gear meshing point, E P is the elastic modulus of the driving gear, E G is the elastic modulus of the driven gear, is the Poisson's ratio of the driving gear material, is the Poisson's ratio of the driven gear material;

[0092] Sliding friction coefficient f for:

[0093] ;

[0094] ;

[0095] In the formula, μ' is the dynamic viscosity of the lubricating oil, Ra is the gear surface roughness, SR is the slip ratio;

[0096] Effective elastic modulus E E for:

[0097] ;

[0098] Minimum film thickness h m for:

[0099] ;

[0100] In the formula, is the viscosity-pressure coefficient of the lubricating oil, μ is the dynamic viscosity of the lubricating oil;

[0101] Sliding loss P S and rolling loss P R for:

[0102] ;

[0103] ;

[0104] In the formula, V S is the relative sliding speed, B' is the effective width of the gear, ε α is the lateral contact ratio, β b is the helix angle on the base circle.

[0105] Furthermore, the method of determining the heat source of the driving gear and the driven gear at each meshing point by using the heat distribution coefficient includes:

[0106] The heat distribution coefficient of the driving wheel and the driven wheel is calculated by the following formula:

[0107] ;

[0108] ;

[0109] In the formula, is the heat distribution coefficient of the driving wheel, is the heat distribution coefficient of the driven wheel, is the thermal conductivity of the driving gear, is the density of the driving gear, is the specific heat capacity of the driving gear, is the thermal conductivity of the driven gear, is the density of the driven gear, is the specific heat capacity of the driven gear;

[0110] According to the heat distribution coefficient, the heat source generated by the heat generated when the driving wheel is engaged is calculated using the following formula S P The heat source generated when meshing with the driven wheel S G :

[0111] ;

[0112] ;

[0113] Furthermore, encapsulating the modeled load-bearing interface model into an analysis system includes:

[0114] The fluid domain modeling calculation method, the solid domain thermal network method, and the gear friction heat calculation method are integrated into one system. The oil immersion depth, rotation speed, and lubricating oil temperature are set as the input parameters of the system. The oil stirring power loss and temperature change of the gear pair are used as the output of the system. The system is used to obtain the operating data of the gear pair at the load-bearing interface, simulate the operating data through the integrated calculation method, and output the heat source calculation results of the load-bearing interface, thereby realizing the comparative analysis of the solution data and the experimental data.

[0115] According to another aspect of the present invention, a transmission system load-bearing interface modeling system is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any of the above-described transmission system load-bearing interface modeling methods when executing the computer program.

[0116] According to another aspect of the present invention, a storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the transmission system load-bearing interface modeling method as described in any one of the above items are implemented.

[0117] The transmission system load-bearing interface modeling method provided in the embodiment of the present invention uses an overlapping grid and a VOF model to calculate the multiphase flow evolution process inside the gear transmission; by discretizing the gear body into a number of temperature nodes and thermal resistances, a solid domain thermal network model is established to achieve rapid iteration of the temperature field of the gear body; based on the coordinate system of gear dynamics, the position of any meshing point is solved, and the heat source of the master and driven gears at each meshing point is calculated by combining empirical formulas, fluid dynamics data and heat distribution coefficients, and the calculated heat source is applied to the solid domain thermal network model for calculation; then the fluid domain modeling calculation method, the solid domain thermal network method, and the gear friction heat generation calculation method are integrated into a system, the oil immersion depth, rotation speed, and lubricating oil temperature are set as input parameters of the system, and the oil stirring power loss and temperature change of the gear pair are used as outputs, which can quickly realize comparative analysis of the solved data with the experimental data under the same working conditions.

[0118] The present invention can achieve rapid response of the gear body temperature to multiphase thermal flow field data, perform iterative simulation with smaller and larger time steps in the fluid domain and the solid domain, and capture the real multiphase thermal flow behavior and the adaptive evolution of the gear body temperature with a small time cost. On the one hand, it can provide a reference for the research process of temperature changes and multiphase flow behaviors inside the helical gear reducer, and on the other hand, it improves the research efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0119] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0120] Figure 1 A schematic diagram of a flow chart of a transmission system load-bearing interface modeling method according to an embodiment of the present invention;

[0121] Figure 2 It is the structural diagram of the gear pair;

[0122] Figure 3 It is a schematic diagram of overlapping grids in the load-bearing interface model;

[0123] Figure 4 It is a schematic diagram of the principle of data exchange strategy for the carrier interface model;

[0124] Figure 5 It is a schematic diagram of various types of surfaces of gear pairs in the thermal network model;

[0125] Figure 6 This is the schematic diagram of the solid domain thermal network model;

[0126] Figure 7 This is the principle diagram for solving the meshing point position during the gear meshing process;

[0127] Figure 8 Schematic diagram of the transmission system load-bearing interface model system. DETAILED DESCRIPTION

[0128] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0129] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0130] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, product, or apparatus comprising a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0131] Example 1, reference Figure 1 , Figure 1 FIG. 1 is a flow chart of a method for modeling a load-bearing interface of a transmission system according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0132] S1, establishing a three-dimensional model of the load-bearing interface, and meshing the fluid domain in the three-dimensional model of the load-bearing interface;

[0133] The load-bearing interface refers to the part of the transmission system that bears loads and stresses. Its performance directly affects the overall performance and life of the transmission system. In the vehicle transmission system, the load-bearing interface is generally a meshing gear pair. A gear pair is a transmission device consisting of two or more gears that transmits rotational force and changes speed and torque through the meshing point. Figure 2 , Figure 2is a schematic diagram of the gear pair structure, such as Figure 2 As shown, the gear pair in this example is a pair of mutually meshing helical gears, including a driving gear and a driven gear.

[0134] The three-dimensional model of the load-bearing interface in S1 can be realized through modeling software such as AutoCAD, 3ds Max, SolidWorks, etc. After the three-dimensional model of the gear pair is established, it is necessary to mesh the fluid domain (i.e., the area where the fluid, such as lubricating oil, flows) in the three-dimensional model. Meshing is the basis of numerical simulation, which discretizes the continuous fluid domain into a series of small units for numerical calculation. In this example, the process of establishing the fluid domain meshing is as follows: the load-bearing interface is divided into the driving wheel area, the driven wheel area and the gear box area. The driving wheel area and the driven wheel area are set in the foreground grid, and the box area is used as the background grid. The grid units of the background grid and the foreground grid are structured hexahedral grids and mixed polyhedron-hexahedral grids, respectively. There are appropriate expansion layers near the wall to ensure the normalized wall distance. Overlapping interfaces are established between the driving wheel area and the box area and between the driven wheel area and the box area. Refer to Figure 3 , Figure 3 It is a schematic diagram of overlapping grids in the carrier interface model, and the overlapping interface is used to realize the transmission of information between the driving wheel area and the box area, and between the driven wheel area and the box area.

[0135] Reference Figure 4 , Figure 4 It is a schematic diagram of the principle of data exchange strategy for the carrier interface model, such as Figure 4 As shown, the modeling of the load-bearing interface of the transmission system in this embodiment mainly includes two parts: the fluid domain and the solid domain. The fluid domain and the solid domain use the VOF model and the thermal network model respectively. Among them, the VOF (Volume of Fluid) model is a numerical method for simulating multiphase flow, which can accurately capture the changes in the phase interface (such as the oil-gas interface). The VOF model can be used to simulate the changes in the phase interface in the multiphase flow in the gear transmission, and then analyze the influence of the fluid on the gear pair. The solid domain part of the gear pair (such as the gear body, bearings, etc.) is modeled using the thermal network model. The thermal network model discretizes the solid domain into several temperature nodes, and describes the temperature distribution of the entire solid domain through the heat conduction relationship between the nodes.

[0136] In any coupling cycle, the number of iterations of the fluid domain and the solid domain is the same, but the iteration time step of the fluid domain ( Δt fluid ) is smaller than the iteration time step of the solid domain ( Δt solid ), when the coupling condition is reached, the convection heat transfer coefficient of the gear and shaft wall in the fluid domain ( h) is transferred to the thermal network model to calculate the convection thermal resistance, and the temperature of each thermal network node is used as the constant temperature boundary condition at the corresponding position in the fluid domain.

[0137] In addition, any transient simulation may cause large fluctuations in simulation data due to numerical iteration instability. In order to prevent the discrete coupling simulation caused by large data deviation, a loosely coupled simulation framework is selected in this example to appropriately scale the coupled data. h Defined as:

[0138] ;

[0139] In the formula, τ and N are the relaxation factor and number of iterations of the coupling cycle, h i is the convective heat transfer coefficient for each iteration.

[0140] S2, determine the simulation conditions, use the VOF model to model the fluid domain of the load-bearing interface, and capture the phase interface in the multiphase flow in the gear transmission;

[0141] The simulation conditions include oil immersion depth, gear speed, lubricating oil temperature, etc. The heat transfer and flow of the fluid domain in the load-bearing interface model is a multiphase thermal-fluid coupling problem. This example uses the VOF model, where the VOF model control equation is as follows:

[0142] Continuity equation:

[0143] ;

[0144] In the formula, ρ is the fluid density, t It's time. is the velocity vector of the fluid;

[0145] Momentum equation:

[0146] ;

[0147] ;

[0148] In the formula, P It's pressure. μ is the dynamic viscosity, is the acceleration due to gravity, is the surface tension, is the surface tension coefficient, is the air volume fraction, is the air density, is the curvature of the air interface, is the air volume fraction, is the lubricating oil volume fraction, is the density of the lubricating oil, is the curvature of the lubricating oil interface, is the lubricating oil volume fraction;

[0149] Energy equation:

[0150] ;

[0151] In the formula, It's energy. is the effective thermal conductivity, T is the temperature, is the energy source term;

[0152] At present, the software ANSYS Fluent does not support the calculation of wall friction heat. Therefore, the energy lost by stirring oil is S E The form of is applied to the fluid domain, and the formula is as follows:

[0153] ;

[0154] In the formula, M P , M P,axle They represent the oil stirring torque of the driving gear (unit: N·m) and the oil stirring torque of the driving gear shaft, M G , M G,axle They represent the oil stirring torque of the driven gear and the oil stirring torque of the driven gear shaft respectively, , Respectively represent the speed of the driving gear and the speed of the driven gear (unit: RPM), V l is the total lubricating oil volume (unit: m 3 );

[0155] The VOF model is used to predict the distribution of each phase and the mixture density within each grid unit. ρ and viscosity μ for:

[0156] ;

[0157] ;

[0158] ;

[0159] In the formula, represents the viscosity of air, Indicates the viscosity of the lubricating oil;

[0160] when =1, it means that the grid cell is full of air, and when =0, it means there is no lubricating oil in the grid unit.

[0161] S3, the solid domain of the load-bearing interface is modeled using a thermal network model, and the solid domain is partially discretized into several temperature nodes;

[0162] To achieve fast iteration of the temperature field, this example uses a thermal network model to model the solid domain. The thermal network model is a mathematical model used to simulate and analyze heat conduction, convection, and radiation processes. TN ), and connect these nodes through thermal resistance (including conductive resistance and convection resistance) to simulate the flow of heat in the system.

[0163] Reference Figure 5 , Figure 5 Schematic diagram of various types of surfaces of gear pairs in the thermal network model, such as Figure 5 As shown, in the thermal network model, the surface types of the gear replica are mainly divided into two parts: thermal flux coupling surface and insulation surface. The end face of the gear shaft is the insulation surface, and the remaining surfaces of the gear and the gear shaft are thermal flux coupling surfaces.

[0164] Reference Figure 6 , Figure 6 This is the schematic diagram of the solid domain thermal network model. Figure 6 (a) is the heat transfer path of the master and slave gears in the gear transmission. The relative sliding and rolling during the meshing process of the gears generate friction heat. Since the thermal conductivity of metal gears is much higher than that of lubricating oil, most of the heat first enters the gears and diffuses inside the gears along the direction from the tooth top to the shaft end. This process can be explained by the thermal resistance. R d Finally, the heat is transferred to the lubricating oil and air by thermal convection, which can be described by the convection thermal resistance R c To simulate.

[0165] based on Figure 6 The heat transfer and generation process in (a) can be used to establish a thermal network model of the gears in the gear transmission, such as Figure 6 (b), heat source ( S ), temperature node( TN )、Thermal resistance( R d )、Convection thermal resistance( R c) are represented by hollow circles, black dots, solid rectangular blocks and diagonal rectangular blocks, respectively. The heat source represents the location where heat is generated, such as the gear meshing surface; the solid domain (such as gears and gear shafts) is discretized into several temperature nodes, which represent the temperature states at different locations in the solid domain; the thermal conductivity connects adjacent temperature nodes to simulate the heat conduction process inside the solid; the convection thermal resistance connects the temperature nodes with the environment (such as lubricating oil and air) to simulate the process of heat transfer to the environment through convection.

[0166] R c Computational requirements TN The regions match the mesh resolution of the fluid domain, so the mesh resolution on the gears and shafts TN The division area cannot be too fine. In this example, the driving gear, driving gear shaft, driven gear, and driven gear shaft are discretized into 6, 14, 12, and 13 temperature nodes respectively. The total temperature node area is divided into M Parts and gear shafts N part, TN Subscript numbers and letters represent TN By solving the temperature of these nodes, the temperature distribution of the entire solid domain can be understood;

[0167] For each temperature node TN , the following energy equation needs to be satisfied:

[0168] ;

[0169] In the formula, Q ij To connect the temperature node TN j and temperature nodes TN i The heat exchange between S i To join TN i The heat source, ρ i , V i , C Pi , T TN,i They are TN i density, volume, specific heat capacity, temperature, n is the number of temperature nodes;

[0170] Based on the above energy equation, the temperature nodes of the gear pair are established TN The transient iterative energy expression of is:

[0171] Heat transfer at the tooth tip node:

[0172] ;

[0173] In the formula, T ave,fluid is the average temperature of the fluid, T TN,1 is the temperature node at the tooth top, T TN,2 is the temperature node of the gear body near the outer side and adjacent to the tooth top, S To join T TN,1 The heat, is the temperature node of the tooth top at time t+1, Δ t represents the solid domain iteration time step, R c is the convective heat transfer thermal resistance, R d,gear is the thermal resistance between nodes on the gear body;

[0174] Heat transfer from the gear body node along the radius of the gear:

[0175] ;

[0176] T TN,3 For T TN,2 Adjacent temperature nodes, It is the temperature node of the gear body near the outer side and adjacent to the tooth top at time t+1;

[0177] Heat transfer at nodes between gears and gear shafts:

[0178] ;

[0179] T TN,m-1 is the temperature node in the gear body close to the shaft, T TN,m is the temperature node between the gear body and the shaft, T TN,m+1 is the temperature node on the shaft close to the gear body, R d,axle is the thermal resistance between nodes on the gear shaft, is the temperature node between the gear body and the shaft at time t+1;

[0180] Heat transfer at nodes on gear shaft:

[0181] ;

[0182] T TN,m+2 On axis andT TN,m+1 Adjacent temperature nodes, It is the temperature node on the axis close to the gear body at time t+1;

[0183] Heat transfer at gear shaft end node:

[0184] ;

[0185] T TN,m+n is the temperature node of the shaft end surface, T TN,m+n-1 On axis and T TN,m+n Adjacent temperature nodes, is the temperature node of the shaft end surface at time t+1;

[0186] According to heat transfer theory, the thermal resistance between nodes on the gear body is for:

[0187] ;

[0188] Farther from the axis TN radius, Closer to the axis TN radius, is the thermal conductivity, B is the tooth width;

[0189] Thermal resistance between nodes on the gear shaft for:

[0190] ;

[0191] l is the temperature node spacing, A is the heat exchange area;

[0192] Convective heat transfer resistance for:

[0193] ;

[0194] are the temperature nodes on the gear and shaft, Q is the convective heat transfer at the wall of the corresponding area in the fluid domain.

[0195] S4, based on gear dynamics, calculate the friction heat generated by the gear pair, obtain the heat source under the meshing state, and apply it to the thermal network model for simulation calculation;

[0196] The heat source in the solid domain thermal network model is generated based on the frictional heat of gear dynamics. The gear dynamics model is used to solve the meshing point position of the gear pair at different times, and the frictional heat power of the gear during the meshing process is calculated. According to the meshing condition and friction power of the gear, the distribution of the heat source on the gear is determined. Then, the heat source data obtained based on the gear dynamics calculation is input into the thermal network model to simulate the heat flow.

[0197] In this example, empirical equations are used to calculate the sliding loss and rolling loss of each meshing point on each meshing line, and the heat distribution coefficient is used to determine the heat source of the driving gear and the driven gear at each meshing point. The average heat source of each meshing line is derived from the heat source of each meshing point, and then a weighted average is performed according to the length of each meshing line to obtain the heat source in the current meshing state. Finally, the heat source of each cycle is averaged to obtain the average heat source during the transmission process. Specifically, S4 includes:

[0198] S41, establishing a coordinate system based on gear dynamics, and solving the positions of each meshing point of the gear pair during the meshing process based on the coordinate system;

[0199] Reference Figure 7 , Figure 7 This is the principle diagram for solving the meshing point position during the gear meshing process. Figure 7 As shown in (a), the meshing process of the gear is determined according to the design parameters of the gear, and the gear node O and the meshing point are respectively B 1( B 1 is the trajectory line of the driven gear tooth top and the theoretical meshing line N 1 N 2) as the origin, establish X'Y' ( Figure 7 (b)) and X"Y" ( Figure 7 (c)) coordinate system, in Figure 7 In (b), the grid lines are discretized by establishing a slope of tan( α t ), we can get the grid points at X'Y' The position in the coordinate system. Figure 7 (c) shows that X"Y" In the coordinate system, according to the meshing point and the base circle helix angle ( β b ) Establish the corresponding meshing line linear function and obtain the length and number of meshing lines ( O ), and the discrete grid points on each meshing line are obtained by coordinate transformation. X'Y' The position in the coordinate system.

[0200] S42, for each meshing point on each meshing line, calculating the sliding loss and the rolling loss using an empirical equation;

[0201] An empirical equation is a mathematical formula that represents one or more empirical relationships using an equation, which can be determined based on experience or experiment.

[0202] In this example, the specific calculation process of sliding loss and rolling loss using empirical equations is as follows:

[0203] Calculate the integrated radius of curvature at the meshing point R CC (Unit: m):

[0204] ;

[0205] In the formula, R C,P It indicates the radius of curvature of the driving gear at the meshing point (unit: m). R C,G Indicates the radius of curvature of the driven gear at the meshing point (unit: m);

[0206] The sliding speed is:

[0207] ;

[0208] ;

[0209] In the formula, V S,P is the sliding speed of the driving gear (unit: m / s), V S,G is the sliding speed of the driven gear (unit: m / s), is the rotation speed of the driving gear (unit: RPM), is the rotation speed of the driven gear (unit: RPM);

[0210] Relative sliding speed V RS and scroll speed V RR for:

[0211] ;

[0212] ;

[0213] Relative slip ratio V SR for:

[0214] ;

[0215] Maximum Hertzian contact stress σ max (Unit: GPa) is:

[0216] ;

[0217] In the formula, F n is the normal force (unit: N), L C is the contact line length of the gear meshing (unit: mm), E P is the elastic modulus of the driving gear, E G is the elastic modulus of the driven gear, is the Poisson's ratio of the driving gear material, is the Poisson's ratio of the driven gear material;

[0218] Sliding friction coefficient f for:

[0219] ;

[0220] ;

[0221] In the formula, μ' is the dynamic viscosity of the lubricating oil (unit: cP), Ra is the gear surface roughness (unit: μm), SR is the slip ratio;

[0222] Effective elastic modulus E E (Unit: Pa) is:

[0223] ;

[0224] Minimum film thickness h m (Unit: m) is:

[0225] ;

[0226] In the formula, is the viscosity-pressure coefficient of the lubricating oil (unit: m 2 / N), μ is the dynamic viscosity of the lubricating oil;

[0227] Sliding loss P S (Unit: W) and rolling loss P R (Unit: W) is:

[0228] ;

[0229] ;

[0230] In the formula, V Sis the relative sliding speed, B' is the effective width of the gear (unit: m), ε α is the lateral contact ratio, β b It is the helix angle on the base circle (unit: rad), where base circle is a professional term for gears, referring to an imaginary circle on an involute cylindrical gear (or cycloid cylindrical gear). When the generating line that forms the involute tooth profile (or the generating circle that forms the cycloid tooth profile) rolls purely on the circumference of this imaginary circle, this imaginary circle is the base circle.

[0231] S43, determining the heat source of the driving gear and the driven gear at each meshing point using the heat distribution coefficient;

[0232] The heat distribution coefficient reflects the distribution ratio of heat between the two contact surfaces during the friction process. Through the heat distribution coefficient, the heat generated by the driving gear and the driven gear at each meshing point can be calculated.

[0233] In this embodiment, the heat distribution coefficient of the driving wheel and the driven wheel is calculated by the following formula:

[0234] ;

[0235] ;

[0236] In the formula, is the heat distribution coefficient of the driving wheel, is the heat distribution coefficient of the driven wheel, is the thermal conductivity of the driving gear, is the density of the driving gear, is the specific heat capacity of the driving gear, is the thermal conductivity of the driven gear, is the density of the driven gear, is the specific heat capacity of the driven gear;

[0237] Calculate the heat source generated by the heat generated when the driving wheel is engaged based on the heat distribution coefficient S P The heat source generated when meshing with the driven wheel S G :

[0238] ;

[0239] ;

[0240] S44, calculating an average heat source of each meshing line according to the heat sources of the driving gear and the driven gear at each meshing point;

[0241] The average heat source for each mesh line is calculated by adding the heat sources of all mesh points on each mesh line and dividing by the number of mesh points.

[0242] S45, performing weighted averaging according to the length of each meshing line to obtain the heat source in the current meshing state;

[0243] The heat source in the current meshing state reflects the total heat generated by friction during the entire meshing process. The weight of each meshing line is determined according to the length of each meshing line, and the total heat source in the current meshing state is obtained by weighted average.

[0244] S46, averaging the heat sources of all calculation cycles in the transmission process to obtain an average heat source in the transmission process;

[0245] The average heat source helps to evaluate the thermal effect of the gear pair during long-term operation. The heat source of all cycles in the running transmission process is averaged to obtain the average heat source in the transmission process.

[0246] In this embodiment, the calculation process of friction heat is mainly divided into three parts. First, a coordinate system based on gear dynamics is established to solve the position of any meshing point; then, the heat source of the master and driven gears at each meshing point is calculated by combining empirical formulas, CFD (Computational Fluid Dynamics) data and heat distribution coefficients; finally, the average heat source of each transmission process is obtained by averaging twice.

[0247] S47, applying the calculated heat source data to the solid domain thermal network model.

[0248] The calculated heat source data, including the heat source of the driving gear and the driven gear at each meshing point, the average heat source of each meshing line, the heat source in the current meshing state, and the average heat source during the transmission process, are applied to the solid domain thermal network model to reflect the thermal effect of the gear pair during the working process.

[0249] S5, encapsulating the modeled load-bearing interface model into an analysis system, wherein the input parameters of the analysis system are the working condition data of the gear pair, and the output parameters are the oil stirring power loss and temperature change of the gear pair.

[0250] Reference Figure 8 , Figure 8It is a schematic diagram of the load-bearing interface model system of the transmission system. The embodiment of the present invention integrates the fluid domain modeling calculation method, the solid domain thermal network method, and the gear friction heat calculation method into one system. The thermal network model is coupled with the VOF model for data exchange, and the information of each physical field in the fluid domain and the solid domain is solved. The oil immersion depth H, the rotation speed n, and the lubricating oil temperature T are set as the input parameters of the system. The oil stirring power loss and temperature change of the gear pair are used as the output of the system. By obtaining the working condition data of the gear pair of the load-bearing interface, the working condition data is simulated and calculated using the integrated calculation method, and the heat source prediction result of the load-bearing interface is output, so as to realize the comparative analysis of the solved data and the experimental data.

[0251] The transmission system load-bearing interface modeling method provided in the embodiment of the present invention uses overlapping grids to calculate the evolution process of multiphase flow inside the gear transmission; by discretizing the gear body into a number of temperature nodes and thermal resistances, a thermal network model of the solid domain is established to achieve rapid iteration of the temperature field of the gear body; based on the coordinate system of gear dynamics, the position of any meshing point is solved, and the empirical formula, CFD data and heat distribution coefficient are combined to obtain the thermal conductivity of the gear body. η , the heat sources of the master and driven gears at each meshing point are calculated, and the calculated heat sources are applied to the solid domain thermal network model for calculation; the fluid domain modeling calculation method, the solid domain thermal network method, and the gear friction heat generation calculation method are integrated into one system, the oil immersion depth, speed, and lubricating oil temperature are set as the input parameters of the system, and the oil stirring power loss and temperature change of the gear pair are used as outputs, so as to quickly realize the comparative analysis of the solution data with the experimental data under the same working conditions.

[0252] Embodiment 2: In this embodiment, a transmission system load-bearing interface modeling system is also provided, which is used to implement the above embodiments and preferred implementations, and the descriptions that have been made will not be repeated. The load-bearing interface modeling system includes a memory and a processor, and the memory stores a computer program. When the processor executes the computer program, the steps of the basic transmission system load-bearing interface modeling method described above are implemented. The specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and this embodiment will not be repeated here.

[0253] An embodiment of the present invention further provides a storage medium, in which a computer program is stored, wherein the computer program is configured to execute the steps of any of the above method embodiments when running.

[0254] Optionally, in this embodiment, the above-mentioned storage medium may include but is not limited to: a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and other media that can store computer programs.

[0255] An embodiment of the present invention further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0256] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation modes, and this embodiment will not be described in detail here.

[0257] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0258] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0259] In the several embodiments provided in this application, it should be understood that the disclosed technical contents can be implemented in other ways.

[0260] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A transmission system load-bearing interface modeling method, characterized in that: include: Establishing a three-dimensional model of a load-bearing interface, wherein the load-bearing interface is a meshing gear pair, and meshing a fluid domain in the three-dimensional model of the load-bearing interface; Determine the simulation conditions, use the VOF model to model the fluid domain of the load-bearing interface, and capture the phase interface in the multiphase flow in the gear transmission; The solid domain of the load-bearing interface is modeled using a thermal network model, and the solid domain is partially discretized into several temperature nodes; Based on gear dynamics, calculate the friction heat generated by the gear pair, obtain the heat source under the meshing state, and apply it to the thermal network model for simulation calculation; The load-bearing interface model after modeling is encapsulated into an analysis system, wherein the input parameters of the analysis system are the working condition data of the gear pair, and the output parameters are the oil stirring power loss and temperature change of the gear pair; The thermal network model is used to model the solid domain of the load-bearing interface, and the solid domain is partially discretized into a number of temperature nodes including: The driving gear, driving gear shaft, driven gear, and driven gear shaft are discretized into 6, 14, 12, and 13 temperature nodes respectively; For each temperature node TN , the following energy equation needs to be satisfied: ； In the formula, Q ij To connect the temperature node TN j and temperature nodes TN i The heat exchange between S i To join TN i The heat source, ρ i , V i , C Pi , T TN,i They are TN i density, volume, specific heat capacity, temperature, n is the number of temperature nodes; Based on the energy equation, each temperature node of the gear pair is established TN The transient iterative energy expression of is: Heat transfer at the tooth tip node: ； In the formula, T ave,fluid is the average temperature of the fluid, T TN,1 is the temperature node at the tooth top, T TN,2 is the temperature node of the gear body near the outer side and adjacent to the tooth top, S To join T TN,1 The heat source, is the temperature node of the tooth top at time t+1, Δ t represents the solid domain iteration time step, R c is the convective heat transfer thermal resistance, R d,gear is the thermal resistance between nodes on the gear body; Heat transfer from the gear body node along the radius of the gear: ； T TN,3 For T TN,2 Adjacent temperature nodes, It is the temperature node of the gear body near the outer side and adjacent to the tooth top at time t+1; Heat transfer at nodes between gears and gear shafts: ； T TN,m-1 is the temperature node close to the shaft in the gear body, T TN,m is the temperature node between the gear body and the shaft, T TN,m+1 is the temperature node on the shaft close to the gear body, R d,axle is the thermal resistance between the nodes on the gear shaft, is the temperature node between the gear body and the shaft at time t+1; Heat transfer at nodes on gear shaft: ； T TN,m+2 On axis and T TN,m+1 Adjacent temperature nodes, It is the temperature node on the axis close to the gear body at time t+1; Heat transfer at gear shaft end node: ； T TN,m+n is the temperature node of the shaft end surface, T TN,m+n-1 On axis and T TN,m+n Adjacent temperature nodes, is the temperature node of the shaft end surface at time t+1; According to heat transfer theory, the thermal resistance between nodes on the gear body is for: ； Farther from the axis TN radius, Closer to the axis TN radius, is the thermal conductivity, B is the tooth width; Thermal resistance between nodes on the gear shaft for: ； l is the temperature node spacing, A is the heat exchange area; Convective heat transfer resistance for: ； are the temperature nodes on the gear and shaft, Q is the convective heat transfer at the wall of the corresponding area in the fluid domain.

2. The transmission system load-bearing interface modeling method according to claim 1, characterized in that: The meshing of the fluid domain in the three-dimensional model of the load-bearing interface comprises: Divide the load-bearing interface into a driving wheel area, a driven wheel area and a gear box area; The driving wheel area and the driven wheel area are set in the foreground grid, and the box area is used as the background grid, wherein the foreground grid unit is a mixed hexahedral grid and the background grid unit is a structured hexahedral grid; An overlapping interface is established between the driving wheel area and the box area, and between the driven wheel area and the box area, and the overlapping interface is used to realize the transmission of information between the driving wheel area and the box area, and between the driven wheel area and the box area; A dilation layer is set between the background mesh and the foreground mesh walls to ensure normalized wall distance.

3. The transmission system load-bearing interface modeling method according to claim 1, characterized in that: The simulation working conditions include oil immersion depth, gear speed, and lubricating oil temperature. The modeling of the fluid domain of the load-bearing interface using the VOF model includes: The VOF model is used to perform multiphase thermal-fluid coupling on the heat transfer and flow in the fluid domain of the load-bearing interface model through the following control equations: Continuity equation: ； In the formula, ρ is the fluid density, t It's time. is the velocity vector of the fluid; Momentum equation: ； ； In the formula, P It's pressure. μ is the dynamic viscosity, is the acceleration due to gravity, is the surface tension, is the surface tension coefficient, is the air volume fraction, is the air density, is the curvature of the air interface, is the air volume fraction, is the lubricating oil volume fraction, is the density of the lubricating oil, is the curvature of the lubricating oil interface, is the lubricating oil volume fraction; Energy equation: ； In the formula, It's energy. is the effective thermal conductivity, T is the temperature, is the energy source term; The energy lost in churning is The form of is applied to the fluid domain, and the formula is as follows: ； In the formula, M P , M P,axle They represent the oil stirring torque of the driving gear and the oil stirring torque of the driving gear shaft respectively. M G , M G,axle They represent the oil stirring torque of the driven gear and the oil stirring torque of the driven gear shaft respectively, , Respectively represent the speed of the driving gear and the speed of the driven gear, V l is the total lubricating oil volume; The VOF model is used to predict the distribution of each phase and the mixture density within each grid unit. ρ and viscosity μ for: ； ； ； In the formula, represents the viscosity of air, Indicates the viscosity of the lubricating oil; when =1, it means that the grid cell is full of air, and when =0, it means there is no lubricating oil in the grid unit.

4. The transmission system load-bearing interface modeling method according to claim 1, characterized in that: The calculation of frictional heat generated by the gear pair based on gear dynamics, obtaining the heat source in the meshing state, and applying it to the thermal network model for simulation calculation includes: Establishing a coordinate system based on gear dynamics, and solving the positions of each meshing point of the gear pair during the meshing process based on the coordinate system; For each meshing point on each meshing line, the sliding loss and rolling loss are calculated using empirical equations; Use the heat distribution coefficient to determine the heat source of the driving gear and the driven gear at each meshing point; According to the heat sources of the driving gear and the driven gear at each meshing point, the average heat source of each meshing line is calculated; The weighted average is taken according to the length of each meshing line to obtain the heat source in the current meshing state; The heat sources of all calculation cycles in the transmission process are averaged to obtain the average heat source in the transmission process; The calculated heat source data are applied to the solid domain thermal network model.

5. The transmission system load-bearing interface modeling method according to claim 4, characterized in that: For each meshing point on each meshing line, the sliding loss and rolling loss are calculated using empirical equations including: Calculate the integrated radius of curvature at the meshing point R CC : ； In the formula, R C,P It represents the radius of curvature of the driving gear at the meshing point. R C,G It represents the radius of curvature of the driven gear at the meshing point; The sliding speed is: ； ； In the formula, V S,P is the sliding speed of the driving gear, V S,G is the sliding speed of the driven gear, is the speed of the driving gear, is the speed of the driven gear; Relative sliding speed V RS and scroll speed V RR for: ； ； Relative slip ratio V SR for: ； Maximum Hertzian contact stress σ max for: ； In the formula, F n is the normal force, L C is the contact line length of the gear meshing, E P is the elastic modulus of the driving gear, E G is the elastic modulus of the driven gear, is the Poisson's ratio of the driving gear material, is the Poisson's ratio of the driven gear material; Sliding friction coefficient f for: ； ； In the formula, μ' is the dynamic viscosity of the lubricating oil, Ra is the gear surface roughness, SR is the slip ratio; effective elastic modulus E E for: ； Minimum film thickness h m for: ； In the formula, is the viscosity-pressure coefficient of the lubricating oil, μ is the dynamic viscosity of the lubricating oil; Sliding loss P S and rolling loss P R for: ； ； In the formula, V S is the relative sliding speed, B' is the effective width of the gear, ε α is the lateral contact ratio, β b is the helix angle on the base circle.

6. The transmission system load-bearing interface modeling method according to claim 5, characterized in that: The heat source of the driving gear and the driven gear at each meshing point determined by the heat distribution coefficient includes: The heat distribution coefficient of the driving wheel and the driven wheel is calculated by the following formula: ； ； In the formula, is the heat distribution coefficient of the driving wheel, is the heat distribution coefficient of the driven wheel, is the thermal conductivity of the driving gear, is the density of the driving gear, is the specific heat capacity of the driving gear, is the thermal conductivity of the driven gear, is the density of the driven gear, is the specific heat capacity of the driven gear; According to the heat distribution coefficient, the heat source generated by the heat generated when the driving wheel is engaged is calculated using the following formula S P The heat source generated when meshing with the driven wheel S G : ； 。 7. The transmission system load-bearing interface modeling method according to claim 1, characterized in that: The encapsulating the modeled load-bearing interface model into an analysis system comprises: The fluid domain modeling calculation method, the solid domain thermal network method, and the gear friction heat calculation method are integrated into one system. The oil immersion depth, rotation speed, and lubricating oil temperature are set as the input parameters of the system. The oil stirring power loss and temperature change of the gear pair are used as the output of the system. The system is used to obtain the operating condition data of the gear pair at the load-bearing interface, simulate the operating condition data through the integrated calculation method, and output the heat source calculation results of the load-bearing interface, thereby realizing the comparative analysis of the solution data and the experimental data.

8. A transmission system load-bearing interface modeling system, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the transmission system load-bearing interface modeling method described in any one of claims 1 to 7 are implemented.

9. A storage medium, characterized in that: The storage medium stores a computer program, which, when executed by a processor, implements the steps of the transmission system load-bearing interface modeling method according to any one of claims 1 to 7.

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