Gear modification method for electric vehicle reducer based on simulation

Abstract

The present invention discloses a gear shaping method for electric vehicle reducer based on simulation. By establishing a simulation model under the whole vehicle boundary taking into account the motor, reducer gear shaft, reducer housing and drive assembly suspension, the shortcomings caused by the different constraint states between the existing simulation model and the actual whole vehicle are solved. By establishing a simulation model under the bench test boundary taking into account the reducer gear shaft, reducer housing and bench mounting plate, the existing bench constraint boundary simulation model does not take into account the influence of the bench mounting plate, resulting in the defect that the simulation design result of the reducer shaping scheme is not good in actual test verification. Thus, the two established boundary simulation models are combined with the simulation error of the simulation model obtained by bench test to achieve indirect calibration of the simulation model established based on the whole vehicle boundary, improve the simulation accuracy of the whole vehicle boundary simulation model, and effectively solve the problem that the simulation model established based on the whole vehicle boundary cannot be calibrated by test.

Description

Technical Field

[0001] The invention relates to the technical field of electric vehicle reducers, and in particular to a simulation-based gear modification method for electric vehicle reducers. Background Art

[0002] With the rapid development of the new energy vehicle industry, pure electric vehicles, as the mainstream models in the new energy field, lack the masking effect of the engine and intake and exhaust noise of transmission internal combustion engine models, and the howling noise of the drive motor and reducer becomes particularly prominent, becoming an important factor affecting the subjective perception of the noise inside the pure electric vehicle.

[0003] In actual work, the gearbox of pure electric vehicles is a rigid-flexible coupling structure. Due to factors such as manufacturing errors, assembly errors, and stress deformation, its gear shafts, bearings, gears, and housings will produce different degrees of elastic deformation, resulting in gear misalignment and tooth surface meshing errors. The emergence of these problems will seriously affect the NVH (noise, vibration, harshness) performance of the gearbox, causing the gearbox to vibrate and make noise. By micro-modifying the gears of the gearbox reducer, the gear meshing misalignment and tooth surface meshing error can be reduced, thereby reducing the amplitude and fluctuation of the transmission error, which is an effective way to solve the vibration and noise problems of the gearbox.

[0004] The transmission error (TE) of gears is an important evaluation index to measure the meshing quality of gears, and the meshing quality will have a direct impact on the transmission system of the gearbox. Ideally, the stiffness of the involute gear pair is infinite and there are no manufacturing and assembly errors, and the gears mesh perfectly along the involute. However, in the actual meshing process, due to the stiffness deformation of the tooth surface and the deflection deformation of the shaft, the driven wheel will deviate from the theoretical position, and the displacement is the transmission error. Transmission error is an important excitation source for the whistling noise problem of gears, so by reducing the transmission error of gears, the vibration and noise of gears can be reduced.

[0005] The tooth surface load distribution is also an important evaluation indicator for measuring the quality of gear meshing. In the actual meshing process, gears usually deviate from the ideal position. The uneven distribution of tooth surface load will cause eccentric load in the gear transmission process, making the gear transmission unstable and generating vibration and noise. Therefore, through the micro-modification of the gear, the tooth surface load distribution can be made more uniform and the occurrence of gear eccentric load can be reduced. When formulating the gear micro-modification plan in actual applications, the transmission error and tooth surface load distribution are comprehensively considered. While reducing the transmission error, the gear contact area is made more centered to reduce the occurrence of gear eccentric load.

[0006] The existing gear modification scheme mainly uses Romax software to build a reducer gear shaft model, and then uses finite element software (Hyper Mesh or ANSYS) to mesh the reducer housing, and according to the constraint state of the reducer on the test bench, constrain the connection surface between the reducer housing and the motor (bench constraint boundary), and import the reducer housing model into Romax software to establish the reducer whole machine model. Through simulation calculation under different load conditions of the model, according to the simulated gear meshing misalignment and gear modification experience, the micro-modification parameters of the gear are designed, and the sample is processed. The bench contact spot test is used to verify whether the gear contact area meets the requirements. If not, the simulation results are compared with the test results according to the gear contact spot test results, and the simulation model is corrected according to the test results. The gear modification parameters are optimized based on the corrected simulation model, and the above steps are repeated until the gear contact area meets the requirements. Finally, the bench noise test is used to verify whether the reducer noise meets the standard.

[0007] The above existing shaping solutions will at least lead to the following problems:

[0008] (1) The design and optimization of existing gear modification schemes are based on the constraint boundary of the test bench, that is, the connection surface between the reducer and the motor needs to be constrained. In the actual vehicle, the reducer and the motor are connected and fixed to the frame through suspension, resulting in the difference between the stress state of the reducer and the constraint state of the test bench, which leads to the difference in the gear meshing misalignment. This may cause the gear modification scheme previously optimized based on the constraint boundary of the test bench to change the gear misalignment after actual installation, resulting in unbalanced load in the gear meshing, which may cause noise problems such as gear whistling.

[0009] (2) In the current actual bench verification, the bench mounting plate is fixed to the bench by bolts, and the reducer is fixed to the bench mounting plate by bolts. Different prototypes have different bench mounting plates. Some prototypes have longer bench mounting plates due to structural feature limitations. In this case, the bench mounting plate will also affect the meshing misalignment of the gears. If the simulation is also performed according to the bench constraint boundary, that is, constraining the connection surface between the reducer and the motor, it will also lead to the above-mentioned problem, that is, the gear modification scheme based on the bench constraint boundary optimization will not meet the reducer noise test standards due to changes in the gear meshing misalignment in the actual bench noise test.

[0010] (3) The conditions of the existing test bench cannot simulate the constraint state of the reducer in the whole vehicle. The contact spot test of the gearbox is generally carried out on the contact spot test bench, that is, the constraint state of the contact spot test bench and the gearbox in the whole vehicle are different. Therefore, if a simulation model is established according to the constraint state of the whole vehicle, the simulation model cannot be calibrated directly through the test results. Therefore, it is impossible to complete the above-mentioned optimization cycle from simulation design to test verification and then to simulation design.

[0011] In summary, the existing technical solutions have the following main problems: on the one hand, the errors caused by boundary differences are not considered in detail; on the other hand, the simulation boundary is established according to the actual constraint state, and there is a deficiency that the simulation model cannot be calibrated directly through experiments. Summary of the invention

[0012] In view of the above, the present invention aims to provide a simulation-based electric vehicle reducer gear shaping method to solve the problem that the existing simulation boundary is inconsistent with the actual situation, resulting in noise in the simulation-optimized gear shaping scheme in the actual bench test or in the whole vehicle, and to solve the problem that in order to eliminate the error caused by the boundary difference, the simulation model is established according to the whole vehicle boundary but the simulation model cannot be calibrated directly through experiments.

[0013] The technical solution adopted by the present invention is as follows:

[0014] The present invention provides a simulation-based gear modification method for an electric vehicle reducer, which includes:

[0015] Establish the reducer gear shaft model and motor rotor model;

[0016] Obtain the finite element network model of the reducer housing and the motor housing;

[0017] Import the finite element mesh models of the reducer housing and the motor housing into the reducer gear shaft model and the motor rotor model respectively, and establish the electric drive assembly simulation model through node connection;

[0018] Based on the electric drive assembly simulation model, the electric drive assembly suspension position and stiffness parameters are obtained, and the suspension model is established;

[0019] Defining the suspension node connection on the suspension model to obtain a full-vehicle boundary simulation model of the reducer;

[0020] On the basis of establishing the reducer gear shaft model and obtaining the reducer housing finite element network model, the finite element network model of the bench mounting plate is obtained;

[0021] Connect and constrain the bench mounting plate to the reducer housing, and set a grounding constraint between the bench mounting plate and the bench connection surface;

[0022] The finite element mesh model of the reducer housing and the bench mounting plate is imported into the reducer gear shaft model, and the reducer bench test boundary simulation model is obtained through node connection;

[0023] Performing simulation calculation based on the reducer vehicle boundary simulation model to obtain a first gear modification scheme, and combining the first gear modification scheme with the reducer bench test boundary simulation model to obtain a simulation error of the reducer bench test boundary simulation model;

[0024] Based on the simulation error, the reducer vehicle boundary simulation model is corrected, and the optimized gear modification parameters are combined with the first gear modification scheme to obtain a target gear modification scheme based on the vehicle boundary.

[0025] In at least one possible implementation, obtaining the simulation error of the reducer bench test boundary simulation model includes:

[0026] Preliminarily determine the gear modification parameters in the first gear modification scheme through simulation calculation;

[0027] Combined with the reducer bench test boundary simulation model, the gear meshing misalignment, gear contact spots and transmission errors are simulated;

[0028] Conduct bench contact spot test based on simulation results;

[0029] Based on the bench contact spot test results, the gear modification parameters are adjusted to make the simulation results correspond to the test results;

[0030] The difference between the adjusted gear modification parameters and the gear modification parameters in the first gear modification scheme is used as the simulation error of the bench test boundary simulation model.

[0031] In at least one possible implementation, obtaining a target gear modification scheme based on the whole vehicle boundary includes:

[0032] Based on the simulation error, the reducer vehicle boundary simulation model is corrected, and a second gear modification scheme is obtained;

[0033] Performing simulation optimization on the modified vehicle boundary simulation model of the reducer to obtain an optimized modification scheme for the third gear;

[0034] Obtaining a change in a gear modification parameter in a third gear modification scheme and a gear modification parameter in a second gear modification scheme;

[0035] The variation is superimposed on the first gear modification scheme to obtain the target gear modification scheme.

[0036] In at least one possible implementation, the establishment of the suspension model includes: determining the position coordinate information of the left suspension, right suspension and rear suspension points in the electric drive assembly simulation model according to the actual layout of the electric drive assembly in the vehicle, and establishing the corresponding simulated suspension axis.

[0037] In at least one possible implementation manner, defining a suspension node connection on the suspension model includes:

[0038] Setting a suspension position node for connecting the shell on the simulation suspension shaft;

[0039] According to the position of the mounting bolt hole of each suspension bracket on the shell, the node number corresponding to the internal grid of the mounting bolt hole is obtained;

[0040] The node serial numbers are imported into the suspension model, and the mounting bolt hole nodes corresponding to each suspension bracket are respectively connected with each of the suspension position nodes.

[0041] In at least one possible implementation manner, after establishing the suspension model, the method further includes:

[0042] Set ground connection constraints on the suspension model; and,

[0043] The isotropic stiffness information of the suspension is obtained, and the isotropic stiffness values ​​corresponding to the suspension position nodes used to connect the shell in the suspension model are modified.

[0044] In at least one possible implementation, establishing the reducer gear shaft model and the motor rotor model includes: configuring the reducer gear shaft and the motor rotor shaft to be an integral shaft or connecting the two via a spline.

[0045] In at least one possible implementation, the gear shaping method further includes: in the process of establishing the electric drive assembly simulation model, establishing a stator model and dividing the grid according to the motor stator parameters, and connecting the divided motor stator finite element network model and the motor housing finite element grid model through nodes.

[0046] The main design concept of the present invention is that, on the one hand, by establishing a simulation model under the whole vehicle boundary that takes into account the motor, reducer gear shaft, reducer housing and drive assembly suspension, the shortcomings caused by the different constraint states in the existing simulation model and the actual whole vehicle are solved. On the other hand, by establishing a simulation model under the bench test boundary that takes into account the reducer gear shaft, reducer housing and bench mounting plate, the existing bench constraint boundary simulation model does not take into account the influence of the bench mounting plate, resulting in the simulation design results of the reducer modification scheme being poor in actual test verification. Thus, the simulation model of the whole vehicle boundary and the bench test boundary simulation model established are combined with the bench test results to obtain the simulation error of the simulation model, and the simulation model established based on the whole vehicle boundary is indirectly calibrated to improve the simulation accuracy of the whole vehicle boundary simulation model, effectively solving the problem that the simulation model established based on the whole vehicle boundary cannot be calibrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0048] Figure 1 A flowchart of a simulation-based electric vehicle reducer gear modification method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0050] The present invention proposes an embodiment of a simulation-based electric vehicle reducer gear modification method. Specifically, Figure 1 shown, including:

[0051] Step S1, establishing a reducer gear shaft model and a motor rotor model; wherein the above model can be established based on Romax, and preferably, the reducer gear shaft and the motor rotor shaft can be set as an integral shaft or connected by a spline according to actual conditions. In addition, a stator model can also be established according to the motor stator parameters.

[0052] Step S2, obtaining the finite element network model of the reducer housing and the motor housing; the reducer housing and the motor housing can be meshed by using finite element software (HyperMesh or ANSYS).

[0053] Step S3, import the divided finite element mesh models of the reducer housing and the motor housing into the reducer gear shaft model and the motor rotor model respectively, and establish an electric drive assembly simulation model through node connection (wherein each bearing involved can be connected to the position of the bearing seat in the housing model); in some embodiments, the motor stator model can be automatically meshed by software and connected to the imported motor housing finite element mesh model through nodes.

[0054] The rigid-flexible coupling model of the motor-reducer gear shaft-reducer housing is established through the above-mentioned embodiments.

[0055] Then, executing step S4, based on the electric drive assembly simulation model, obtaining the electric drive assembly suspension position and stiffness parameters, and establishing a suspension model;

[0056] In actual operation, the position coordinate information of the left suspension, right suspension and rear suspension points in the electric drive assembly simulation model can be determined according to the actual layout of the electric drive assembly in the vehicle, and the corresponding simulated suspension axis can be established, thereby approximately equivalent to the actual suspension of the electric drive assembly.

[0057] Step S5, defining the suspension node connection on the suspension model to obtain a reducer vehicle boundary simulation model;

[0058] Specifically, a suspension position node for connecting the shell can be set on the simulated suspension shaft, and according to the installation position of each suspension bracket on the shell, that is, the position of the mounting bolt hole of each bracket, the node number corresponding to the internal grid of the bolt hole is read through the finite element software, and the node number corresponding to each mounting bolt hole is imported into the model, and the mounting bolt hole nodes corresponding to each bracket of the left suspension, right suspension and rear suspension are respectively connected to each of the suspension position nodes. Preferably, first, a ground connection constraint is set on the suspension model; second, the isotropic stiffness information of the suspension is obtained, and the isotropic stiffness value corresponding to the suspension position node for connecting the shell in the suspension model is modified to simulate the actual constraint state of the electric drive assembly (that is, the constraint state of the whole vehicle).

[0059] Step S6, based on establishing the reducer gear shaft model and obtaining the reducer housing finite element network model, obtaining the bench mounting plate finite element network model;

[0060] Step S7, connect and constrain the bench mounting plate and the reducer housing (such as establishing RBE2 units at the bolt holes of the two), and set a grounding constraint between the bench mounting plate and the bench connection surface.

[0061] Step S8, import the divided finite element mesh model of the reducer housing and the bench mounting plate into the reducer gear shaft model, and obtain the reducer bench test boundary simulation model through node connection (wherein each bearing involved is connected to the corresponding position of the housing bearing seat through a node), that is, establish a rigid-flexible coupling model of the bench mounting plate-reducer gear shaft-reducer housing.

[0062] As mentioned above, the bench mounting plate has an impact on the meshing misalignment of the gears, especially for some prototypes whose bench mounting plates are too long due to the structural feature limit. At this time, the impact of the mounting plate on the meshing misalignment of the gears is more significant. Considering the mounting plate, the meshing misalignment may increase by several microns. However, this change may not be distinguished through the actual contact spot test, that is, the gear modification scheme based on the bench constraint boundary simulation design, during the actual bench test, due to the influence of the bench mounting plate (the meshing misalignment increases), the previous gear modification scheme will actually appear overloaded, but this change is small, and may not be distinguished through the contact spot test, but during the reducer bench noise test, it will be found that the noise test results are not good, the gear excitation is large, and other problems. Therefore, the present invention considers the influence of the bench mounting plate in the simulation design stage to improve the simulation accuracy.

[0063] Step S9, performing simulation calculation based on the reducer vehicle boundary simulation model to obtain a first gear modification scheme, and combining the first gear modification scheme with the reducer bench test boundary simulation model to obtain a simulation error of the reducer bench test boundary simulation model;

[0064] The specific process of obtaining the simulation error of the reducer bench test boundary simulation model can be referred to as follows:

[0065] Preliminarily determine the gear modification parameters in the first gear modification scheme through simulation calculation;

[0066] Combined with the reducer bench test boundary simulation model, the gear meshing misalignment, gear contact spots and transmission errors are simulated;

[0067] Conduct bench contact spot test based on simulation results;

[0068] Based on the bench contact spot test results, the gear modification parameters are adjusted to make the simulation results correspond to the test results;

[0069] The difference between the adjusted gear modification parameters and the gear modification parameters in the first gear modification scheme is used as the simulation error of the bench test boundary simulation model.

[0070] Step S10: based on the simulation error, correct the reducer vehicle boundary simulation model, and use the optimized gear modification parameters to merge with the first gear modification scheme to obtain a target gear modification scheme based on the vehicle boundary.

[0071] Specifically, obtaining a target gear modification scheme based on the vehicle boundary includes:

[0072] Based on the simulation error, the reducer vehicle boundary simulation model is corrected, and a second gear modification scheme is obtained;

[0073] Performing simulation optimization on the modified vehicle boundary simulation model of the reducer to obtain an optimized modification scheme for the third gear;

[0074] Obtaining a change in a gear modification parameter in a third gear modification scheme and a gear modification parameter in a second gear modification scheme;

[0075] The variation is superimposed on the first gear modification scheme to obtain the target gear modification scheme.

[0076] In summary, the main design concept of the present invention is that, on the one hand, by establishing a simulation model under the whole vehicle boundary that takes into account the motor, reducer gear shaft, reducer housing and drive assembly suspension, the shortcomings caused by the different constraint states in the existing simulation model and the actual whole vehicle are solved. On the other hand, by establishing a simulation model under the bench test boundary that takes into account the reducer gear shaft, reducer housing and bench mounting plate, the existing bench constraint boundary simulation model does not take into account the influence of the bench mounting plate, resulting in the simulation design results of the reducer modification scheme being poor in actual test verification. Thus, the simulation model of the whole vehicle boundary and the bench test boundary simulation model established are combined with the bench test results to obtain the simulation error of the simulation model, and the simulation model established based on the whole vehicle boundary is indirectly calibrated to improve the simulation accuracy of the whole vehicle boundary simulation model, effectively solving the problem that the simulation model established based on the whole vehicle boundary cannot be calibrated.

[0077] In the embodiments of the present invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. A and B may be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c may represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c may be single or multiple.

[0078] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred methods can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the present invention is not limited to the scope of implementation shown in the drawings, and all changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the specification and drawings, should be within the protection scope of the present invention.

Claims

1. A simulation-based gear modification method for electric vehicle reducer, characterized in that: include: Establish the reducer gear shaft model and motor rotor model; Obtain the finite element network model of the reducer housing and the motor housing; Import the finite element mesh models of the reducer housing and the motor housing into the reducer gear shaft model and the motor rotor model respectively, and establish the electric drive assembly simulation model through node connection; Based on the electric drive assembly simulation model, the electric drive assembly suspension position and stiffness parameters are obtained, and the suspension model is established; Defining the suspension node connection on the suspension model to obtain a full-vehicle boundary simulation model of the reducer; On the basis of establishing the reducer gear shaft model and obtaining the reducer housing finite element network model, the finite element network model of the bench mounting plate is obtained; Connect and constrain the bench mounting plate to the reducer housing, and set a grounding constraint between the bench mounting plate and the bench connection surface; The finite element mesh model of the reducer housing and the bench mounting plate is imported into the reducer gear shaft model, and the reducer bench test boundary simulation model is obtained through node connection; Performing simulation calculation based on the reducer vehicle boundary simulation model to obtain a first gear modification scheme, and combining the first gear modification scheme with the reducer bench test boundary simulation model to obtain a simulation error of the reducer bench test boundary simulation model; Based on the simulation error, the reducer vehicle boundary simulation model is corrected, and the optimized gear modification parameters are combined with the first gear modification scheme to obtain a target gear modification scheme based on the vehicle boundary.

2. The electric vehicle reducer gear modification method based on simulation according to claim 1 is characterized in that: The simulation error of the reducer bench test boundary simulation model obtained includes: Preliminarily determine the gear modification parameters in the first gear modification scheme through simulation calculation; Combined with the reducer bench test boundary simulation model, the gear meshing misalignment, gear contact spots and transmission errors are simulated; Conduct bench contact spot test based on simulation results; Based on the bench contact spot test results, the gear modification parameters are adjusted to make the simulation results correspond to the test results; The difference between the adjusted gear modification parameters and the gear modification parameters in the first gear modification scheme is used as the simulation error of the bench test boundary simulation model.

3. The electric vehicle reducer gear modification method based on simulation according to claim 1 is characterized in that: The target gear modification scheme based on the vehicle boundary is obtained by: Based on the simulation error, the reducer vehicle boundary simulation model is corrected, and a second gear modification scheme is obtained; Performing simulation optimization on the modified vehicle boundary simulation model of the reducer to obtain an optimized modification scheme for the third gear; Obtaining a change in a gear modification parameter in a third gear modification scheme and a gear modification parameter in a second gear modification scheme; The variation is superimposed on the first gear modification scheme to obtain the target gear modification scheme.

4. The electric vehicle reducer gear modification method based on simulation according to claim 1, characterized in that: The establishment of the suspension model includes: determining the position coordinate information of the left suspension, right suspension and rear suspension points in the electric drive assembly simulation model according to the actual layout of the electric drive assembly in the vehicle, and establishing the corresponding simulation suspension axis.

5. The electric vehicle reducer gear modification method based on simulation according to claim 4 is characterized in that: Defining a suspension node connection on the suspension model includes: Setting a suspension position node for connecting the shell on the simulation suspension shaft; According to the position of the mounting bolt hole of each suspension bracket on the shell, the node number corresponding to the internal grid of the mounting bolt hole is obtained; The node serial numbers are imported into the suspension model, and the mounting bolt hole nodes corresponding to each suspension bracket are respectively connected with each of the suspension position nodes.

6. The electric vehicle reducer gear modification method based on simulation according to claim 1, characterized in that: After the suspension model is established, it also includes: Set ground connection constraints on the suspension model; and, The isotropic stiffness information of the suspension is obtained, and the isotropic stiffness values ​​corresponding to the suspension position nodes used to connect the shell in the suspension model are modified.

7. The electric vehicle reducer gear modification method based on simulation according to claim 1, characterized in that: The establishing of the reducer gear shaft model and the motor rotor model includes: setting the reducer gear shaft and the motor rotor shaft as an integral shaft or connecting the two through a spline.

8. The electric vehicle reducer gear modification method based on simulation according to any one of claims 1 to 7, characterized in that: The gear modification method also includes: in the process of establishing the electric drive assembly simulation model, establishing a stator model and dividing the grid according to the motor stator parameters, and connecting the divided motor stator finite element network model and the motor housing finite element grid model through nodes.

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