An electric drive axle oil temperature simulation calculation method and device based on bench test correction

Abstract

This application discloses a method and apparatus for simulating and calculating the oil temperature of an electric drive axle based on bench test corrections, relating to the field of automotive component design technology. This application reduces the gap between simulation and experimental results and improves the accuracy of electric drive axle oil temperature simulation by using bench test corrections and iterative optimizations to address bearing losses, gear oil churning losses, and gear friction losses.

Description

Technical Field

[0001] This application relates to the field of automotive component design technology, and in particular to a method and apparatus for simulating and calculating the oil temperature of an electric drive axle based on bench testing correction. Background Technology

[0002] The electric drive axle is the core drive unit of an electric vehicle. It generates a significant amount of heat during operation, and poor heat dissipation can easily lead to vehicle malfunctions. Therefore, after the electric drive axle is designed, a saturation temperature rise test is required to assess its heat dissipation capacity and ensure vehicle reliability.

[0003] Currently, to reduce R&D costs and shorten the R&D cycle, the industry typically uses software-based, process-oriented calculations for saturated temperature rise simulation. However, existing saturated temperature rise simulations show significant discrepancies between the simulation results and experimental results, making it impossible for the simulation results to accurately reflect the true heat dissipation state of the electric drive bridge. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a method and apparatus for simulating and calculating the oil temperature of an electric drive axle based on bench test correction. This method can narrow the gap between simulation results and test results, and improve the accuracy of the oil temperature simulation for the electric drive axle.

[0005] The embodiments of this application disclose the following technical solutions: In a first aspect, this application discloses a simulation calculation method for oil temperature of an electric drive axle based on bench test correction, the method comprising: By establishing a static analysis model of the shaft system of the electric drive axle system that takes into account the deformation of the housing, the gear force and gear speed of each gear of the electric drive axle under the temperature rise test condition, as well as the bearing force and bearing speed of each bearing, are obtained. Based on the bearing force and bearing speed of each bearing, the theoretical bearing loss is determined, and based on the theoretical bearing loss and the actual bearing loss determined by bench test, the bearing loss correction coefficient is determined. Based on the gear speed of each gear, the theoretical oil churning loss of the gear is determined, and based on the theoretical oil churning loss of the gear and the measured oil churning loss of the gear determined by conducting an no-load test on the electric drive bridge, the gear oil churning loss correction coefficient is determined. Based on the gear forces on each gear, the theoretical friction loss of the gears is determined, and based on the theoretical friction loss of the gears and the measured friction loss of the gears determined by loading tests on the electric drive bridge, the gear friction loss correction coefficient is determined. Based on the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient, the theoretical bearing loss, the theoretical gear oil churning loss, and the theoretical gear friction loss are corrected respectively to obtain the corrected bearing loss, the corrected gear oil churning loss, and the corrected gear friction loss. The theoretical lubricating oil temperature is determined based on the corrected bearing loss, the corrected gear churning loss, and the corrected gear friction loss. If, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, it is determined that the preset conditions are not met, then at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient shall be iteratively adjusted.

[0006] Optionally, the measured oil churning loss of the gear is determined as follows: The input power of the first motor was determined by conducting an no-load test on the electric drive bridge. The measured oil churning loss of the gear is determined based on the difference between the input power of the first motor and the corrected bearing loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss.

[0007] Optionally, the measured friction loss of the gear is determined as follows: By conducting a loading test on the electric drive bridge with a preset high torque, the input power of the second motor and the output power of the test bench were determined. The total loss of the bench test is determined based on the difference between the input power of the second motor and the output power of the bench. The measured friction loss of the gear is determined based on the difference between the total loss from the bench test and the first value; the first value is the sum of the corrected bearing loss and the corrected gear oil churning loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss; the corrected gear oil churning loss is the product of the gear oil churning loss correction coefficient and the theoretical gear oil churning loss.

[0008] Optionally, the formula for determining the theoretical lubricating oil temperature is as follows: P bear +P gear1 +P gear2 =Q ca (T) oil ) + Q r ; Among them, P bear For the corrected bearing loss, P gear1 For the corrected gear churning loss, P gear2 For the corrected gear friction loss, T oilQ is the theoretical lubricating oil temperature. ca (T) oil The theoretical lubricating oil temperature is T. oil Heat dissipation at time, Q r This refers to the heat dissipation of the external heat sink.

[0009] Optionally, if it is determined, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, that the preset conditions are not met, then iteratively adjusting at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient includes: If the ratio of the absolute difference between the theoretical lubricating oil temperature and the measured lubricating oil temperature to the measured lubricating oil temperature is greater than a first threshold, then at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient is iteratively adjusted.

[0010] Secondly, this application discloses an electric drive axle oil temperature simulation calculation device based on bench test correction. The device includes: a data acquisition module, a first determination module, a second determination module, a third determination module, a data correction module, a fourth determination module, and an iterative adjustment module. The data acquisition module is used to acquire the gear force and gear speed of each gear of the electric drive axle under the temperature rise test condition, as well as the bearing force and bearing speed of each bearing, by establishing a static analysis model of the shaft system of the electric drive axle system that takes into account the deformation of the housing. The first determining module is used to determine the theoretical bearing loss based on the bearing force and bearing speed of each bearing, and to determine the bearing loss correction coefficient based on the theoretical bearing loss and the actual bearing loss determined by bench test. The second determining module is used to determine the theoretical oil churning loss of the gears based on the gear speed of each gear, and to determine the gear oil churning loss correction coefficient based on the theoretical oil churning loss of the gears and the measured oil churning loss of the gears determined by conducting an no-load test on the electric drive bridge. The third determining module is used to determine the theoretical friction loss of the gears based on the gear force of each gear, and to determine the gear friction loss correction coefficient based on the theoretical friction loss of the gears and the measured friction loss of the gears determined by loading tests on the electric drive bridge. The data correction module is used to correct the theoretical bearing loss, theoretical gear oil churning loss, and theoretical gear friction loss according to the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient, respectively, to obtain the corrected bearing loss, the corrected gear oil churning loss, and the corrected gear friction loss. The fourth determining module is used to determine the theoretical lubricating oil temperature based on the corrected bearing loss, the corrected gear churning loss, and the corrected gear friction loss. The iterative adjustment module is used to iteratively adjust at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient if it is determined, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, that the preset conditions are not met.

[0011] Optionally, the second determining module is specifically used for: determining the input power of the first motor by conducting an unload test on the electric drive bridge; determining the measured oil churning loss of the gear based on the difference between the input power of the first motor and the corrected bearing loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss.

[0012] Optionally, the third determining module is specifically used for: determining the input power of the second motor and the output power of the test bench by performing a loading test on the electric drive bridge with a preset high torque; determining the total test bench loss based on the difference between the input power of the second motor and the output power of the test bench; determining the measured friction loss of the gear based on the difference between the total test bench loss and a first value; the first value is the sum of the corrected bearing loss and the corrected gear churning loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss; the corrected gear churning loss is the product of the gear churning loss correction coefficient and the theoretical gear churning loss.

[0013] Optionally, the formula for determining the theoretical lubricating oil temperature is as follows: P bear +P gear1 +P gear2 =Q ca (T) oil ) + Q r ; Among them, P bear For the corrected bearing loss, P gear1 For the corrected gear churning loss, P gear2 For the corrected gear friction loss, T oil Q is the theoretical lubricating oil temperature. ca (T) oil The theoretical lubricating oil temperature is T. oil Heat dissipation at time, Q r This refers to the heat dissipation of the external heat sink.

[0014] Optionally, the iterative adjustment module is specifically used to: if the ratio of the absolute difference between the theoretical lubricating oil temperature and the measured lubricating oil temperature to the measured lubricating oil temperature is greater than a first threshold, then iteratively adjust at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient.

[0015] Compared with the prior art, this application has the following beneficial effects: This application discloses a method and apparatus for simulating and calculating the oil temperature of an electric drive axle based on bench test correction. The method includes: establishing a static analysis model of the shaft system of the electric drive axle considering housing deformation; obtaining the gear force and gear speed of each gear, as well as the bearing force and bearing speed of each bearing under temperature rise test conditions; determining the theoretical bearing loss based on the bearing force and bearing speed of each bearing, and determining a bearing loss correction coefficient based on the theoretical bearing loss and the measured bearing loss determined through bench test; determining the theoretical gear churning loss based on the gear speed of each gear, and determining a gear churning loss correction coefficient based on the theoretical gear churning loss and the measured gear churning loss determined through no-load test of the electric drive axle; and determining the gear oil temperature simulation calculation method and apparatus based on the gear force of each gear. Theoretical friction loss is calculated, and a gear friction loss correction coefficient is determined based on the theoretical gear friction loss and the measured gear friction loss determined through loading tests on the electric drive axle. Based on the bearing loss correction coefficient, gear oil churning loss correction coefficient, and gear friction loss correction coefficient, the theoretical bearing loss, theoretical gear oil churning loss, and theoretical gear friction loss are corrected respectively to obtain the corrected bearing loss, corrected gear oil churning loss, and corrected gear friction loss. The theoretical lubricating oil temperature is determined based on these corrected bearing loss, corrected gear oil churning loss, and corrected gear friction loss. If the theoretical lubricating oil temperature and the measured lubricating oil temperature do not meet the preset conditions, at least one of the bearing loss correction coefficient, gear oil churning loss correction coefficient, and gear friction loss correction coefficient is iteratively adjusted. Therefore, this application, through bench test correction and iterative optimization of bearing loss, gear oil churning loss, and gear friction loss, narrows the gap between simulation results and experimental results, and improves the accuracy of electric drive axle oil temperature simulation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1A flowchart illustrating a method for simulating and calculating the oil temperature of an electric drive axle based on bench test correction, provided in this application embodiment; Figure 2 This is a schematic diagram of an electric drive bridge oil temperature simulation calculation device based on bench test correction, provided in an embodiment of this application. Detailed Implementation

[0018] As described earlier, to reduce R&D costs and shorten the R&D cycle, the industry typically uses software-based, process-oriented calculations for saturated temperature rise simulation. However, existing saturated temperature rise simulations show significant discrepancies between the simulation results and experimental results, making it impossible for the simulation results to accurately reflect the true heat dissipation state of the electric drive bridge.

[0019] Through research, the inventors proposed a method and device for simulating and calculating the oil temperature of an electric drive axle based on bench test correction. This application reduces the gap between simulation results and test results and improves the accuracy of electric drive axle oil temperature simulation by using bench test correction and iterative optimization for bearing loss, gear oil churning loss and gear friction loss.

[0020] 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 with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0021] See Figure 1 The figure is a flowchart of a method for simulating and calculating the oil temperature of an electric drive axle based on bench testing, provided in an embodiment of this application. The method includes: S101: By establishing a static analysis model of the shaft system of the electric drive axle system that considers the deformation of the housing, the gear force and gear speed of each gear of the electric drive axle under the temperature rise test condition, as well as the bearing force and bearing speed of each bearing, are obtained.

[0022] The heat generated by an electric drive axle comes from two sources: bearing wear and gear wear. Bearing wear refers to the energy loss caused by internal friction and lubrication resistance within the bearing, which is ultimately converted into heat. Gear wear refers to the energy loss caused by the relative sliding, rolling, and agitation of lubricating oil between the gear teeth, which also ultimately converts into heat.

[0023] In traditional technologies, the housing of an electric drive axle is often assumed to be absolutely rigid. However, in practical applications, the housing of the electric drive axle will undergo some deformation, which will have several effects: slight offset of the bearing mounting position, misalignment of the shaft center positions, and changes in the gear meshing state, thus causing changes in the forces on the gears and bearings. Changes in the forces on the gears and bearings will also change the losses, ultimately affecting the oil temperature prediction. Therefore, this application establishes a static analysis model of the shaft system of the electric drive axle that considers housing deformation in order to make the subsequent oil temperature calculation of the electric drive axle closer to the actual operating conditions.

[0024] By establishing a static analysis model of the shaft system of the electric drive axle system that takes into account the deformation of the housing, the bearing force and bearing speed of each bearing, as well as the gear force and gear speed of each gear, are determined.

[0025] S102: Determine the theoretical bearing loss based on the bearing force and bearing speed of each bearing, and determine the bearing loss correction coefficient based on the theoretical bearing loss and the actual bearing loss determined by bench testing.

[0026] A1: Determine the theoretical bearing loss based on the bearing force and bearing speed of each bearing.

[0027] In one specific implementation, the theoretical bearing loss P of the i-th bearing can be determined by the following formula (1) based on the bearing force and bearing speed of each bearing. bi : (1) Among them, P bi Let τ be the theoretical bearing loss (in kW) of the i-th bearing. bear M is the correction factor for the bearing test bench. bi Let n be the bearing friction torque of the i-th bearing (in Nm). i Let M be the bearing speed of the i-th bearing (in r / min). Specifically, the bearing friction torque M of the i-th bearing in formula (1) is calculated using the following formula (2). bi : (2) Among them, M bi Let fi be the bearing friction torque of the i-th bearing, f0 be the viscous friction coefficient, and v be the kinematic viscosity of the lubricating oil (in m³). 2 / s), n b For the bearing speed, d mi Let f1 be the bearing mean diameter of the i-th bearing, f1 be the load friction coefficient, P1 be the equivalent bearing load, f2 be the sealing friction coefficient, and F be the bearing pitch diameter. aiLet fi be the bearing force of the i-th bearing. Specifically, the viscous friction coefficient f0, load friction coefficient f1, and sealing friction coefficient f2 are usually provided by the bearing manufacturer or obtained through bench testing.

[0028] A2: The actual bearing wear was determined through bench testing.

[0029] A3: Determine the bearing loss correction factor based on the theoretical bearing loss and the actual bearing loss.

[0030] It should be noted that after determining the bearing loss correction coefficient, the corrected bearing loss needs to be determined based on the product of the bearing loss correction coefficient and the theoretical bearing loss, so that the absolute difference between the corrected bearing loss and the measured bearing loss satisfies the first preset condition. For example, the first preset condition can be shown in the following formula (3): (3) Among them, P bi For the corrected bearing loss of the i-th bearing, P bi-test Let be the measured bearing loss of the i-th bearing. Formula (3) stipulates that the relative error between the corrected bearing loss and the measured bearing loss must be controlled within 15%.

[0031] S103: Determine the theoretical oil churning loss of the gears based on the gear speed of each gear, and determine the gear oil churning loss correction coefficient based on the theoretical oil churning loss of the gears and the measured oil churning loss of the gears determined by conducting no-load tests on the electric drive bridge.

[0032] Gear losses are divided into two types: churning loss and friction loss. Churning loss refers to the energy consumed by the gear as it continuously immerses, agitates, and ejects lubricating oil during rotation; this energy is ultimately converted into heat. Friction loss refers to the energy consumed by the frictional resistance generated during gear meshing, resulting from the relative sliding of the gear teeth; this energy is also ultimately converted into heat.

[0033] B1: Determine the theoretical oil churning loss of the gears based on the gear speed of each gear.

[0034] In one specific implementation, the theoretical oil churning loss of the gear can be determined by the following formula (4): (4) Among them, P gear1 Let τ be the theoretical oil churning loss of the i-th gear (in kW). gear T is the correction factor for the first gear test bench. gear n is the gear drag torque. gi Let be the gear rotation speed of the i-th gear.

[0035] B2: Measured oil churning loss of gears determined by no-load test of electric drive bridge.

[0036] First, the input power of the first motor was determined by conducting an no-load test on the electric drive bridge.

[0037] Subsequently, the measured oil churning loss of the gear is determined based on the difference between the input power of the first motor and the corrected bearing loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss.

[0038] B3: Determine the gear oil churning loss correction coefficient based on the theoretical and actual gear oil churning losses.

[0039] It should be noted that after determining the gear churning loss correction coefficient, the corrected gear churning loss needs to be determined based on the product of the gear churning loss correction coefficient and the theoretical gear churning loss, so that the absolute difference between the corrected gear churning loss and the measured gear churning loss satisfies the second preset condition. For example, the second preset condition can be shown in the following formula (5): (5) Among them, P gear1 For the corrected gear churning loss, P g-test1 The measured oil churning loss of the gear is given by formula (5). Formula (5) stipulates that the relative error between the corrected oil churning loss of the gear and the measured oil churning loss of the gear must be controlled within 15%.

[0040] S104: Determine the theoretical friction loss of the gears based on the gear forces on each gear, and determine the gear friction loss correction coefficient based on the theoretical friction loss of the gears and the measured friction loss of the gears determined by loading tests on the electric drive bridge.

[0041] C1: Determine the theoretical friction loss of the gears based on the forces acting on each gear.

[0042] In one specific implementation, the theoretical friction loss of the gear can be determined by the following formula (6): (6) Among them, P gear2 For the theoretical friction loss of gears, τ gear-2 F is the correction factor for the second gear test bench. gear-t β is the tangential force (unit: N) acting on the gear. b α is the base circle helix angle. t Let 'b' be the end face pressure angle, 'b' be the gear tooth width, and 'v' be the end face t For tangential acceleration, For the working pressure angle, ρ cred For the combined radius of curvature, R is the dynamic viscosity of the lubricating oil at the operating temperature. a F is the arithmetic mean roughness of the tooth surface. N V is the normal stress on the tooth surface. s The sliding speed is on the meshing line of the tooth surface.

[0043] C2: The measured friction loss of the gears is determined by loading the electric drive bridge.

[0044] First, by conducting a load test on the electric drive bridge with a preset high torque, the input power of the second motor and the output power of the test bench were determined.

[0045] Subsequently, the total loss of the bench test was determined based on the difference between the input power of the second motor and the output power of the bench.

[0046] Finally, the measured friction loss of the gear is determined based on the difference between the total loss from the bench test and the first value; the first value is the sum of the corrected bearing loss and the corrected gear churning loss; the corrected bearing loss is the product of the bearing loss correction factor and the theoretical bearing loss; the corrected gear churning loss is the product of the gear churning loss correction factor and the theoretical gear churning loss.

[0047] C3: Determine the gear friction loss correction coefficient based on the theoretical and measured friction losses of the gear.

[0048] It should be noted that after determining the gear friction loss correction coefficient, the corrected gear friction loss needs to be determined based on the product of the gear friction loss correction coefficient and the theoretical gear friction loss, so that the absolute difference between the corrected gear friction loss and the measured gear friction loss satisfies the third preset condition. For example, the third preset condition can be shown in the following formula (7): (7) Among them, P gear2 For the corrected gear friction loss, P g-test2 The measured friction loss of the gear is given by formula (7). Formula (7) stipulates that the relative error between the corrected gear friction loss and the measured gear friction loss must be controlled within 15%.

[0049] S105: Based on the bearing loss correction coefficient, gear oil churning loss correction coefficient, and gear friction loss correction coefficient, the theoretical bearing loss, theoretical gear oil churning loss, and theoretical gear friction loss are corrected respectively to obtain the corrected bearing loss, corrected gear oil churning loss, and corrected gear friction loss.

[0050] S106: Determine the theoretical lubricating oil temperature based on the corrected bearing loss, corrected gear churning loss, and corrected gear friction loss.

[0051] In one specific implementation, the theoretical lubricating oil temperature T can be determined by the following formula (8). oil : P bear +P gear1 +P gear2 =Q ca (T) oil ) + Q r (8) Among them, P bear For the corrected bearing loss, P gear1 For the corrected gear churning loss, P gear2 For the corrected gear friction loss, Q ca (T) oil The theoretical lubricating oil temperature is T. oil Heat dissipation at time, Q r The heat dissipation of the external heat sink is denoted as . It can be understood that the left side of equation (8) is the total heat generation power, and the right side of equation (8) is the total heat dissipation power.

[0052] S107: If, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, it is determined that the preset conditions are not met, then at least one of the bearing loss correction coefficient, gear oil churning loss correction coefficient, and gear friction loss correction coefficient shall be iteratively adjusted.

[0053] First, the actual lubricating oil temperature T is determined by installing a temperature sensor on the gearbox. test Subsequently, if the fourth preset condition shown in the following formula (9) is satisfied based on the theoretical lubricating oil temperature and the actual lubricating oil temperature, then the design is approved.

[0054] |T oil -T test | / T test ×100%≤10%(9)

[0055] If, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, it is determined that the preset condition shown in the above formula (9) is not met (i.e., if the ratio of the absolute difference between the theoretical lubricating oil temperature and the measured lubricating oil temperature to the measured lubricating oil temperature is greater than the first threshold, for example, the first threshold can be 10%), then at least one of the bearing loss correction coefficient, gear oil churning loss correction coefficient and gear friction loss correction coefficient is iteratively adjusted.

[0056] In summary, this application discloses a simulation calculation method for oil temperature of electric drive axles based on bench test correction. By bench test correction and iterative optimization of bearing loss, gear oil churning loss and gear friction loss, this application narrows the gap between simulation results and test results and improves the accuracy of oil temperature simulation of electric drive axles.

[0057] See Figure 2 The figure is a schematic diagram of an electric drive axle oil temperature simulation calculation device based on bench test correction provided in an embodiment of this application. The electric drive axle oil temperature simulation calculation device 200 based on bench test correction includes: a data acquisition module 201, a first determination module 202, a second determination module 203, a third determination module 204, a data correction module 205, a fourth determination module 206, and an iterative adjustment module 207.

[0058] The data acquisition module 201 is used to acquire the gear force and gear speed of each gear of the electric drive axle under the temperature rise test condition, as well as the bearing force and bearing speed of each bearing, by establishing a static analysis model of the shaft system of the electric drive axle system that takes into account the deformation of the housing. The first determining module 202 is used to determine the theoretical bearing loss based on the bearing force and bearing speed of each bearing, and to determine the bearing loss correction coefficient based on the theoretical bearing loss and the actual bearing loss determined by bench test. The second determining module 203 is used to determine the theoretical oil churning loss of the gears based on the gear speed of each gear, and to determine the gear oil churning loss correction coefficient based on the theoretical oil churning loss of the gears and the measured oil churning loss of the gears determined by conducting no-load tests on the electric drive bridge. The third determining module 204 is used to determine the theoretical friction loss of the gears based on the gear force of each gear, and to determine the gear friction loss correction coefficient based on the theoretical friction loss of the gears and the measured friction loss of the gears determined by loading tests on the electric drive bridge. The data correction module 205 is used to correct the theoretical bearing loss, theoretical gear oil churning loss, and theoretical gear friction loss according to the bearing loss correction coefficient, gear oil churning loss correction coefficient, and gear friction loss correction coefficient, respectively, to obtain the corrected bearing loss, corrected gear oil churning loss, and corrected gear friction loss. The fourth determining module 206 is used to determine the theoretical lubricating oil temperature based on the corrected bearing loss, the corrected gear churning loss, and the corrected gear friction loss. The iterative adjustment module 207 is used to iteratively adjust at least one of the bearing loss correction coefficient, gear oil churning loss correction coefficient, and gear friction loss correction coefficient if it is determined, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, that the preset conditions are not met.

[0059] In one specific implementation, the second determining module 203 is specifically used to: determine the input power of the first motor by conducting an no-load test on the electric drive bridge; determine the measured oil churning loss of the gear based on the difference between the input power of the first motor and the corrected bearing loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss.

[0060] In one specific implementation, the third determining module 204 is specifically used to: determine the input power of the second motor and the output power of the test bench by performing a loading test on the electric drive bridge with a preset high torque; determine the total test bench loss based on the difference between the input power of the second motor and the output power of the test bench; determine the measured friction loss of the gear based on the difference between the total test bench loss and the first value; the first value is the sum of the corrected bearing loss and the corrected gear churning loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss; the corrected gear churning loss is the product of the gear churning loss correction coefficient and the theoretical gear churning loss.

[0061] In one specific implementation, the formula for determining the theoretical lubricating oil temperature is as follows: P bear +P gear1 +P gear2 =Q ca (T) oil ) + Q r ; Among them, P bear For the corrected bearing loss, P gear1 For the corrected gear churning loss, P gear2 For the corrected gear friction loss, T oil Q is the theoretical lubricating oil temperature. ca (T) oil The theoretical lubricating oil temperature is T. oil Heat dissipation at time, Q r This refers to the heat dissipation of the external heat sink.

[0062] In one specific implementation, the iterative adjustment module 207 is specifically used to: if the ratio of the absolute difference between the theoretical lubricating oil temperature and the measured lubricating oil temperature to the measured lubricating oil temperature is greater than a first threshold, then iteratively adjust at least one of the bearing loss correction coefficient, gear oil churning loss correction coefficient, and gear friction loss correction coefficient.

[0063] In summary, this application discloses an electric drive axle oil temperature simulation calculation device based on bench test correction. By bench test correction and iterative optimization of bearing loss, gear oil churning loss and gear friction loss, this application narrows the gap between simulation results and test results and improves the accuracy of electric drive axle oil temperature simulation.

[0064] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the device and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The device and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of the solution in this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0065] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A simulation calculation method for oil temperature of an electric drive axle based on bench test correction, characterized in that, The method includes: By establishing a static analysis model of the shaft system of the electric drive axle system that takes into account the deformation of the housing, the gear force and gear speed of each gear of the electric drive axle under the temperature rise test condition, as well as the bearing force and bearing speed of each bearing, are obtained. Based on the bearing force and bearing speed of each bearing, the theoretical bearing loss is determined, and based on the theoretical bearing loss and the actual bearing loss determined by bench test, the bearing loss correction coefficient is determined. Based on the gear speed of each gear, the theoretical oil churning loss of the gear is determined, and based on the theoretical oil churning loss of the gear and the measured oil churning loss of the gear determined by conducting an no-load test on the electric drive bridge, the gear oil churning loss correction coefficient is determined. Based on the gear forces on each gear, the theoretical friction loss of the gears is determined, and based on the theoretical friction loss of the gears and the measured friction loss of the gears determined by loading tests on the electric drive bridge, the gear friction loss correction coefficient is determined. Based on the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient, the theoretical bearing loss, the theoretical gear oil churning loss, and the theoretical gear friction loss are corrected respectively to obtain the corrected bearing loss, the corrected gear oil churning loss, and the corrected gear friction loss. The theoretical lubricating oil temperature is determined based on the corrected bearing loss, the corrected gear churning loss, and the corrected gear friction loss. If, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, it is determined that the preset conditions are not met, then at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient shall be iteratively adjusted.

2. The method according to claim 1, characterized in that, The method for determining the measured oil churning loss of the gear is as follows: The input power of the first motor was determined by conducting an no-load test on the electric drive bridge. The measured oil churning loss of the gear is determined based on the difference between the input power of the first motor and the corrected bearing loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss.

3. The method according to claim 1, characterized in that, The method for determining the measured friction loss of the gear is as follows: By conducting a loading test on the electric drive bridge with a preset high torque, the input power of the second motor and the output power of the test bench were determined. The total loss of the bench test is determined based on the difference between the input power of the second motor and the output power of the bench. The measured friction loss of the gear is determined based on the difference between the total loss from the bench test and the first value. The first value is the sum of the corrected bearing loss and the corrected gear churning loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss; the corrected gear churning loss is the product of the gear churning loss correction coefficient and the theoretical gear churning loss.

4. The method according to claim 1, characterized in that, The formula for determining the theoretical lubricating oil temperature is as follows: P bear +P gear1 +P gear2 =Q ca (T oil )+Q r ; Among them, P bear For the corrected bearing loss, P gear1 For the corrected gear churning loss, P gear2 For the corrected gear friction loss, T oil Q is the theoretical lubricating oil temperature. ca (T) oil The theoretical lubricating oil temperature is T. oil Heat dissipation at time, Q r This refers to the heat dissipation of the external heat sink.

5. The method according to claim 1, characterized in that, If, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, it is determined that the preset conditions are not met, then at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient is iteratively adjusted, including: If the ratio of the absolute difference between the theoretical lubricating oil temperature and the measured lubricating oil temperature to the measured lubricating oil temperature is greater than a first threshold, then at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient is iteratively adjusted.

6. A simulation calculation device for oil temperature of an electric drive axle based on bench test correction, characterized in that, The device includes: a data acquisition module, a first determination module, a second determination module, a third determination module, a data correction module, a fourth determination module, and an iterative adjustment module; The data acquisition module is used to acquire the gear force and gear speed of each gear of the electric drive axle under the temperature rise test condition, as well as the bearing force and bearing speed of each bearing, by establishing a static analysis model of the shaft system of the electric drive axle system that takes into account the deformation of the housing. The first determining module is used to determine the theoretical bearing loss based on the bearing force and bearing speed of each bearing, and to determine the bearing loss correction coefficient based on the theoretical bearing loss and the actual bearing loss determined by bench test. The second determining module is used to determine the theoretical oil churning loss of the gears based on the gear speed of each gear, and to determine the gear oil churning loss correction coefficient based on the theoretical oil churning loss of the gears and the measured oil churning loss of the gears determined by conducting an no-load test on the electric drive bridge. The third determining module is used to determine the theoretical friction loss of the gears based on the gear force of each gear, and to determine the gear friction loss correction coefficient based on the theoretical friction loss of the gears and the measured friction loss of the gears determined by loading tests on the electric drive bridge. The data correction module is used to correct the theoretical bearing loss, theoretical gear oil churning loss, and theoretical gear friction loss according to the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient, respectively, to obtain the corrected bearing loss, the corrected gear oil churning loss, and the corrected gear friction loss. The fourth determining module is used to determine the theoretical lubricating oil temperature based on the corrected bearing loss, the corrected gear churning loss, and the corrected gear friction loss. The iterative adjustment module is used to iteratively adjust at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient if it is determined, based on the theoretical lubricating oil temperature and the measured lubricating oil temperature, that the preset conditions are not met.

7. The apparatus according to claim 6, characterized in that, The second determining module is specifically used for: determining the input power of the first motor by conducting an no-load test on the electric drive bridge; determining the measured oil churning loss of the gear based on the difference between the input power of the first motor and the corrected bearing loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss.

8. The apparatus according to claim 6, characterized in that, The third determining module is specifically used to: determine the input power of the second motor and the output power of the test bench by performing a loading test on the electric drive bridge with a preset high torque; and determine the total test bench loss based on the difference between the input power of the second motor and the output power of the test bench. The measured friction loss of the gear is determined based on the difference between the total loss from the bench test and the first value. The first value is the sum of the corrected bearing loss and the corrected gear churning loss; the corrected bearing loss is the product of the bearing loss correction coefficient and the theoretical bearing loss; the corrected gear churning loss is the product of the gear churning loss correction coefficient and the theoretical gear churning loss.

9. The apparatus according to claim 6, characterized in that, The formula for determining the theoretical lubricating oil temperature is as follows: P bear +P gear1 +P gear2 =Q ca (T oil )+Q r ; Among them, P bear For the corrected bearing loss, P gear1 For the corrected gear churning loss, P gear2 For the corrected gear friction loss, T oil Q is the theoretical lubricating oil temperature. ca (T) oil The theoretical lubricating oil temperature is T. oil Heat dissipation at time, Q r This refers to the heat dissipation of the external heat sink.

10. The apparatus according to claim 6, characterized in that, The iterative adjustment module is specifically used to: if the ratio of the absolute difference between the theoretical lubricating oil temperature and the measured lubricating oil temperature to the measured lubricating oil temperature is greater than a first threshold, then iteratively adjust at least one of the bearing loss correction coefficient, the gear oil churning loss correction coefficient, and the gear friction loss correction coefficient.

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