Engineering truck drive axle differential structure optimization method

Abstract

The invention relates to the technical field of automobiles, and provides an engineering vehicle drive axle differential structure optimization method which comprises the following steps: establishing a main reducer model and a differential model; based on the parameters of the to-be-optimized drive axle and the first reverse dragging working condition, an initial load spectrum parameter set is obtained; extracting a first maximum stress point; updating the differential mechanism model into a transition differential mechanism model; extracting a gear parameter set, and calculating a rotating internal friction torque, a sliding internal friction torque, a steering outer side internal friction torque and a steering inner side internal friction torque based on the second reverse dragging working condition, the gear parameter set and the initial load spectrum parameter set; updating the initial load spectrum parameter group into an updated load spectrum parameter group; extracting a second maximum stress point; and updating the transition differential mechanism model into the final differential mechanism model. By means of the method, a traditional engineering vehicle drive axle differential mechanism can be optimized, and the anti-fatigue performance of the traditional engineering vehicle drive axle differential mechanism under the reverse dragging working condition meeting the kinetic energy recovery requirement of an electric engine is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobiles, in particular to an engineering vehicle drive axle differential structure optimization method. BACKGROUND

[0002] With the increasing proportion of electric drive commercial vehicles year by year, as an important part of the automobile transmission system, the electric drive axle is gradually developing and affecting the power and economy of the automobile.

[0003] The drive axle of the engineering vehicle currently has the characteristics of low cost, small product variation and mature technology, such as direct drive axle. The drive axle of the mainstream heavy engineering vehicle adopts a single-stage reducer, and the power is transmitted by double curved gear. When driving forward, the driving bevel gear drives the driven bevel gear to rotate, and when driving backward, the driven bevel gear drives the driving bevel gear to rotate.

[0004] The drive axle of the electric drive commercial vehicle in the prior art has good kinetic energy recovery performance, while the traditional drive axle structure used by the engineering vehicle only meets the forward driving load working condition and is not optimized for the reverse driving and towing load working condition. The traditional engineering vehicle drive axle has low requirements for the reverse towing performance, while the electric motor has higher requirements for the reverse towing performance due to the kinetic energy recovery characteristics. If the traditional engineering vehicle drive axle is directly used for reverse kinetic energy recovery, the differential of the drive axle has insufficient fatigue resistance to the reverse towing working condition due to the shell, and problems such as shell displacement deformation and shell fracture are prone to occur. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide an engineering vehicle drive axle differential structure optimization method. The present application models the main reducer and differential of the engineering vehicle drive axle, inputs different load spectrum parameters according to different reverse towing working conditions, simulates, extracts the positions of the differential shell under greater stress, and optimizes the structure of the differential shell. The present application aims to solve the technical problems of the conventional engineering vehicle drive axle differential in the prior art, such as insufficient fatigue resistance to the reverse towing working condition, and prone to shell displacement deformation and shell fracture.

[0006] In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme: An engineering vehicle drive axle differential structure optimization method, comprising the following steps: Establishing a main reducer model and a differential model based on a drive axle to be optimized; Obtaining an initial load spectrum parameter group based on the parameters of the drive axle to be optimized and a first reverse towing working condition; obtaining a first stress cloud map through finite element analysis based on the main reducer model, the differential model and the initial load spectrum parameter set, and extracting a first maximum stress point from the first stress cloud map; updating the differential model into a transition differential model according to the first maximum stress point; extracting a gear parameter set from the parameters of the to-be-optimized drive axle, calculating a rotating internal friction torque, a sliding internal friction torque, a steering outer side internal friction torque and a steering inner side internal friction torque based on a second reverse traction working condition, the gear parameter set and the initial load spectrum parameter set; obtaining a plurality of updated load working conditions based on the rotating internal friction torque, the sliding internal friction torque, the steering outer side internal friction torque and the steering inner side internal friction torque, adding the plurality of updated load working conditions in the load working conditions corresponding to the initial load spectrum parameter set to update the initial load spectrum parameter set into an updated load spectrum parameter set; obtaining a second stress cloud map through finite element analysis based on the main reducer model, the transition differential model and the updated load spectrum parameter set, and extracting a second maximum stress point from the second stress cloud map; updating the transition differential model into a final differential model according to the second maximum stress point.

[0007] Compared with the prior art, the beneficial effects of the present application are that: by analyzing the parameters of the to-be-optimized drive axle itself and the first reverse traction working condition, the initial load spectrum parameters loaded on the main reducer model and the differential model are obtained, the first maximum stress point on the shell of the differential model is analyzed through finite element analysis, that is, the point position that is most stressed and most prone to fatigue under the first reverse traction working condition, so as to perform targeted structural optimization and reinforcement; the second reverse traction working condition is more complex than the first reverse traction working condition, the load caused by the friction inside the differential is analyzed by combining the second reverse traction working condition and the related parameters of the internal gears of the to-be-optimized drive axle, so as to obtain the updated load spectrum parameters, further simulate the stress condition of the transition differential model, further obtain the second maximum stress point, so as to further optimize the structure of the transition differential model for the more complex reverse traction working condition, and the differential structure optimized based on the traditional engineering vehicle drive axle differential improves the anti-fatigue performance under the reverse traction working condition meeting the electric motor kinetic energy recovery requirement, reduces the stress accumulation on the surface of the differential shell, and prevents the problems of differential shell displacement deformation and even differential shell fracture due to the large stress of local point positions.

[0008] Further, the step of establishing the main reducer model and the differential model based on the to-be-optimized drive axle comprises: establishing a bearing sub-model based on the actual bearing model of the to-be-optimized drive axle; The bevel gear pair model is established by using a bevel gear pair command, and the bevel gear pair model is modified based on the actual tooth profile parameters of the to-be-optimized drive axle to obtain a master and driven bevel gear pair model; The main reducer model is established based on the bearing sub-model and the master and driven bevel gear pair model; An initial differential housing model is established based on the actual state of the to-be-optimized drive axle, the initial differential housing model is meshed, and the left shell material and the right shell material of the initial differential housing model are set to obtain a final differential housing model; The differential model is established based on the final differential housing model and the master and driven bevel gear pair model.

[0009] Further, the initial load spectrum parameter group includes input rotation speed, output rotation speed, input torque, output torque, input power, output power, continuous running time, and working temperature.

[0010] Further, the step of updating the differential model to a transition differential model according to the first maximum stress point includes: positionally comparing the first maximum stress point with the differential model; if the first maximum stress point is located at the left shell of the differential model, increasing the large surface thickness of the left shell of the differential model to obtain a transition differential model; if the first maximum stress point is located at the right shell of the differential model, increasing the first fillet of the right shell of the differential model to obtain a transition differential model.

[0011] Further, the gear parameter group includes a planetary gear pressure angle, a planetary gear pitch angle, a half shaft gear pressure angle, a planetary gear and planetary shaft mounting hole radius, a planetary gear spherical radius, a planetary gear back spherical radius, a half shaft gear pitch circle radius, a planetary gear friction coefficient, and a half shaft gear friction coefficient.

[0012] Further, the formula of the rotational internal friction torque is:

[0013] wherein, represents the rotational internal friction, represents the torque transmitted by the differential, represents the pitch circle radius of the half shaft gear, represents the friction coefficient between the planetary gear and the differential housing, represents the planetary gear spherical radius, represents the planetary gear and planetary shaft mounting hole radius, represents the planetary gear pressure angle, Indicates the pitch cone angle of a planetary gear. This indicates the radius of the spherical back surface of the planetary gear.

[0014] Furthermore, the formula for the sliding internal friction torque is:

[0015] in, This represents the sliding internal friction torque. This indicates the torque transmitted by the differential. This indicates the pitch circle radius of the half-shaft gear. This represents the coefficient of friction between the planetary gears and their shafts. Indicates the radius of the mounting holes for the planetary gears and planetary shafts. Indicates the pressure angle of the planetary gear. This indicates the pitch cone angle of a planetary gear.

[0016] Furthermore, the formula for the steering outer internal friction torque is:

[0017] in, This indicates the internal friction torque on the outside of the steering wheel. This represents the coefficient of friction between the half-shaft gear and the differential housing. This indicates the torque transmitted by the differential. This represents the internal friction force during rotation. This represents the sliding internal friction torque. This indicates the pitch circle radius of the half-shaft gear. Indicates the pressure angle of the planetary gear. This indicates the pressure angle of the half-shaft gear.

[0018] Furthermore, the formula for the internal friction torque on the steering inner side is:

[0019] in, This indicates the internal friction torque on the inside of the steering wheel. This represents the coefficient of friction between the half-shaft gear and the differential housing. This indicates the torque transmitted by the differential. This represents the internal friction force during rotation. This represents the sliding internal friction torque. This indicates the pitch circle radius of the half-shaft gear. Indicates the pressure angle of the planetary gear. This indicates the pressure angle of the half-shaft gear.

[0020] Furthermore, the step of updating the transition differential model to the final differential model based on the second maximum stress point includes: positionally compare the second maximum stress point with the transition differential model; if the second maximum stress point is located at the left shell of the transition differential model, modify the stiffener of the left shell of the transition differential model to obtain a final differential model; if the second maximum stress point is located at the right shell of the transition differential model, increase the first round corner or the second round corner of the right shell of the transition differential model to obtain a final differential model. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 a flow chart of the method for optimizing the structure of the differential of the drive axle of the engineering vehicle in the embodiment of the present application; Figure 2 an optimization schematic diagram of the left shell in the method for optimizing the structure of the differential of the drive axle of the engineering vehicle in the embodiment of the present application; Figure 3 a schematic diagram of the first round corner and the second round corner in the method for optimizing the structure of the differential of the drive axle of the engineering vehicle in the embodiment of the present application; Explanation of Main Element Symbols 110, large surface; 120, stiffener; 210, first round corner; 220, second round corner.

[0022] The following detailed description will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. Several embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present application is more thorough and complete.

[0024] It should be noted that when an element is referred to as being "fixed" to another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "left", "right", and similar expressions used herein are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0026] Referring to Figure 1 The engineering vehicle drive axle differential structure optimization method in the embodiment of the application comprises the following steps: Step S10: establishing a main reducer model and a differential model based on the drive axle to be optimized; Preferably, the main reducer model adopts simplified modeling, only bearing and gear models are established, in order to reflect the shell stress distribution of the differential model, the shell needs to be meshed to obtain a finite element stiffness model, and then the shell stress distribution is obtained according to the axial force and other data transmitted to the shell by the gear.

[0027] The step S10 comprises: S110: establishing a bearing sub-model based on the actual bearing model of the drive axle to be optimized; S120: establishing a bevel gear sub-model by using a bevel gear pair command, and modifying the bevel gear sub-model based on the actual tooth profile parameters of the drive axle to be optimized to obtain a master and driven bevel gear sub-model; S130: establishing the main reducer model based on the bearing sub-model and the master and driven bevel gear sub-model; S140: establishing an initial differential shell model based on the actual state of the drive axle to be optimized, meshing the initial differential shell model, and setting the left shell material and the right shell material of the initial differential shell model to obtain a final differential shell model; S150: establishing the differential model based on the final differential shell model and the master and driven bevel gear sub-model.

[0028] Preferably, S110-S150, the bearing corresponding to the actual bearing model of the drive axle to be optimized is selected from the Romax database, the bearing sub-model and the master and driven bevel gear sub-model are established by Romax, the simplified main reducer model comprises the bearing sub-model and the master bevel gear sub-model, the initial differential shell model is meshed in a tetrahedral grid form, the final differential shell model is imported into Romax, the differential model comprises the final differential shell model, the driven bevel gear sub-model and other gear models inside the differential, and the other gear models inside the differential are modeled according to the actual state of the drive axle to be optimized.

[0029] Step S20: obtaining an initial load spectrum parameter group based on the parameters of the drive axle to be optimized and the first reverse towing working condition; Preferably, the first reverse traction working condition is a straight driving reverse traction working condition, the two-side half shaft torques are equal, and the parameters of the to-be-optimized drive axle include rated input and output torques, initial load working conditions are analyzed in combination with reverse traction requirements and industry standards, and thus initial load spectrum parameter groups available for input in simulation software are obtained.

[0030] In the step S20, the initial load spectrum parameter groups include input rotation speed, output rotation speed, input torque, output torque, input power, output power, continuous operation time, and working temperature.

[0031] Preferably, the input rotation speed is a positive value, the output rotation speed is a negative value, the absolute value ratio of the input rotation speed to the output rotation speed is 5.55, the ratio of the input torque to the output torque is 0.18, the ratio of the input power to the output power is -1, the continuous operation time is 8.2 h, and the working temperature is 70°C.

[0032] In step S30, a first stress cloud map is obtained by finite element analysis based on the main reducer model, the differential mechanism model, and the initial load spectrum parameter groups, and a first maximum stress point is extracted from the first stress cloud map. Preferably, the initial load spectrum parameters are input into a load spectrum analysis module in Romax, specifically, power input and output positions, load time, power flow path, and power input and output parameters are set to complete initial load working condition setting, the load spectrum analysis module is run based on the initial load working condition to analyze and obtain the first stress cloud map based on the finite element stiffness model, the initial load working condition can reflect the power state of each component inside the differential mechanism in the first reverse traction working condition, the power input and output positions are set according to the main reducer model and the differential mechanism model, the load time is equal to the continuous operation time, the input power is determined according to rotation speed and power, the first stress cloud map is a stress cloud map of the differential mechanism housing in the differential mechanism model, the stress value at the first maximum stress point can be compared with the strength limit of the differential mechanism housing, and the strength limit of the differential mechanism housing depends on the materials of the left and right housings.

[0033] In step S40, the differential mechanism model is updated to a transition differential mechanism model according to the first maximum stress point. Understandably, the position of the first maximum stress point is the position where fatigue failure of the differential mechanism model is most likely to occur.

[0034] The step S40 includes: S410: position comparison between the first maximum stress point and the differential mechanism model. S420: If the first maximum stress point is located at the left shell of the differential model, increase the large surface thickness of the left shell of the differential model to obtain a transition differential model; Preferably, referring to Figure 2 The large surface 110 thickness of the left shell of the differential model affects the structural strength of the left shell, and the large surface 110 is usually connected with the reinforcing rib 120 to avoid the problem of insufficient strength.

[0035] S430: If the first maximum stress point is located at the right shell of the differential model, increase the first fillet of the right shell of the differential model to obtain a transition differential model.

[0036] Preferably, referring to Figure 3 The common weak point of the right shell of the differential model corresponds to the position of the gear matching, i.e. the first fillet 210, which is prone to failure such as brushing and cracking. Understandably, when the first maximum stress point appears on the right shell of the differential model, it indicates that the right shell of the differential model is prone to fatigue failure, so the first fillet 210 needs to be increased to strengthen the strength of the right shell of the differential model. Further, after the differential model is modified to the transition differential model, the initial load spectrum parameter set can also be used to analyze the stress of the transition differential model to verify the optimization effect. Specifically, after obtaining the transition differential model, based on the main reducer model, the transition differential model and the initial load spectrum parameter set, the verification stress nephogram is obtained through finite element analysis, and the verification maximum stress point is extracted from the verification stress nephogram. Compare the stress value of the verification maximum stress point with the stress value of the first maximum stress point to determine whether the stress distribution of the transition differential model meets the standard. If the stress value of the verification maximum stress point is reduced by more than 18% compared with the stress value of the first maximum stress point, it is determined that the stress distribution of the transition differential model meets the standard.

[0037] Step S50: Extract the gear parameter set from the parameters of the drive axle to be optimized, calculate the rotating internal friction torque, sliding internal friction torque, steering outer internal friction torque and steering inner internal friction torque based on the second reverse towing working condition, the gear parameter set and the initial load spectrum parameter set; Preferably, the second reverse traction working condition is a curve driving reverse traction working condition, when the vehicle is driving straight, the planetary gear has no self-rotation movement, only exists public rotation, and drives the half shaft gear on both sides to rotate at the same speed and in the same direction, when the vehicle turns, due to the difference of turning radius between the two sides of the vehicle, the internal friction torque of the drive axle differential will cause the self-rotation movement of the two planetary gears in opposite directions, to offset the additional torque of the turning between the wheels, therefore, when analyzing the stress of the transition differential model in the second reverse traction working condition, only the basic initial load spectrum parameter group is not accurate enough, the calculation of the internal friction torque is needed, the internal friction torque is related to the gear related parameters in the optimized drive axle itself. It can be understood that after the basic analysis and optimization of the first reverse traction working condition for straight driving state, the load spectrum parameters are further updated for the second reverse traction working condition of more complex curve driving, which is beneficial to more accurately and comprehensively analyze the stress state of the differential of the optimized drive axle in the reverse traction working condition, so as to carry out more effective structure optimization.

[0038] In the step S50, the gear parameter group includes planetary gear pressure angle, planetary gear pitch angle, half shaft gear pressure angle, planetary gear and planetary shaft mounting hole radius, planetary gear spherical radius, planetary gear back spherical radius, half shaft gear pitch circle radius, planetary gear friction coefficient and half shaft gear friction coefficient.

[0039] Preferably, the half shaft gear back adopts a spherical surface structure with large curvature, the half shaft gear is engaged with the planetary gear, and the planetary gear is fixed in the differential housing through a positioning pin.

[0040] The formula of the rotating internal friction torque is:

[0041] Wherein, The rotating internal friction represents the rotating internal friction, The differential transmitted torque represents the torque transmitted by the differential, The half shaft gear pitch circle radius represents the pitch circle radius of the half shaft gear, The planetary gear and differential housing friction coefficient represents the friction coefficient between the planetary gear and the differential housing, The planetary gear spherical radius represents the spherical radius of the planetary gear, The planetary gear and planetary shaft mounting hole radius represents the mounting hole radius of the planetary gear and the planetary shaft, The planetary gear pressure angle represents the planetary gear pressure angle, The planetary gear pitch angle represents the planetary gear pitch angle, The planetary gear back spherical radius represents the planetary gear back spherical radius.

[0042] The rotating internal friction is the internal friction torque generated by the relative rotation between the planetary gear and the differential housing and the planetary gear and the planetary gear shaft, and the direction of the torque is opposite to the self-rotation direction of the planetary gear.

[0043] The formula of the sliding internal friction torque is:

[0044] wherein, Mf represents the sliding internal friction torque, Tdiff represents the torque transmitted by the differential, R represents the pitch circle radius of the axle gear, μ represents the friction coefficient between the planetary gear and the planetary gear shaft, Rhole represents the mounting hole radius of the planetary gear and the planetary shaft, φ represents the pressure angle of the planetary gear, θ represents the pitch cone angle of the planetary gear.

[0045] The sliding internal friction torque is an internal friction torque generated between the planetary gear and the planetary gear shaft due to relative sliding.

[0046] The formula of the steering outside internal friction torque is:

[0047] wherein, Mf represents the steering outside internal friction torque, μ represents the friction coefficient between the axle gear and the differential housing, Tdiff represents the torque transmitted by the differential, Mf represents the rotational internal friction, Mf represents the sliding internal friction torque, R represents the pitch circle radius of the axle gear, φ represents the pressure angle of the planetary gear, φ represents the pressure angle of the axle gear.

[0048] The steering outside internal friction torque is an internal friction torque generated between the axle gear back spherical surface of the steering outside and the differential housing.

[0049] The formula of the steering inside internal friction torque is:

[0050] wherein, Mf represents the steering inside internal friction torque, μ represents the friction coefficient between the axle gear and the differential housing, Tdiff represents the torque transmitted by the differential, Mf represents the rotational internal friction, Mf represents the sliding internal friction torque, R represents the pitch circle radius of the axle gear, φ represents the pressure angle of the planetary gear, φ represents the pressure angle of the axle gear.

[0051] The turning inner side inner friction torque is an inner friction torque generated between the half shaft gear back spherical surface of the turning inner side and the differential housing.

[0052] Step S60: Based on the rotating inner friction torque, the sliding inner friction torque, the turning outer side inner friction torque and the turning inner side inner friction torque, a plurality of updated load conditions are obtained, and a plurality of the updated load conditions are added in the load conditions corresponding to the initial load spectrum parameter group, so as to update the initial load spectrum parameter group into an updated load spectrum parameter group. Preferably, according to the rotating inner friction torque, the sliding inner friction torque, the turning outer side inner friction torque and the turning inner side inner friction torque, four updated load conditions can be obtained, and the initial load condition and a plurality of the updated load conditions are simultaneously loaded when the load spectrum analysis module is run, specifically, in Romax, the Load Cases in DutyCycle window contains five load conditions, and the Run All DC button can realize the common analysis of all load conditions, and it can be understood that the analysis of the inner friction torque is beneficial to more accurately analyze the load condition in the second reverse towing condition.

[0053] Step S70: Based on the main reducer model, the transition differential model and the updated load spectrum parameter group, a second stress cloud map is obtained through finite element analysis, and a second maximum stress point is extracted from the second stress cloud map. Preferably, the second stress cloud map is a stress cloud map of the differential housing in the transition differential model, and the updated load spectrum parameter group is loaded in the load spectrum analysis module of Romax to obtain the finite element stress condition under the corresponding load spectrum.

[0054] Step S80: According to the second maximum stress point, the transition differential model is updated into a final differential model.

[0055] The step S80 comprises: S810: The second maximum stress point is compared with the position of the transition differential model; S820: If the second maximum stress point is located at the left shell of the transition differential model, the reinforcing rib of the left shell of the transition differential model is modified; S830: If the second maximum stress point is located at the right shell of the transition differential model, the first round corner or the second round corner is increased.

[0056] Preferably, S810-S830, please refer to Figure 2 and Figure 3, the second fillet 220 corresponds to the position near the cross shaft hole, if the second maximum stress point position is close to the first fillet 210, continue to increase the first fillet 210, if the second maximum stress point position is close to the second fillet 220, increase the second fillet 220. Understandably, by analyzing the stress situation under the first reverse towing working condition and the second reverse towing working condition, the structure of the differential housing is gradually and deeply optimized, which can effectively improve the fatigue resistance of the differential on the basis of the traditional engineering vehicle drive axle differential, meet the requirements of electric motor kinetic energy recovery, effectively reduce the stress accumulation on the surface of the differential housing, and prevent the problems of differential housing displacement deformation and even differential housing fracture due to large stress at local points.

[0057] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0058] The above-described embodiments only express several implementation manners of the present application, which are described in detail and specifically, but should not be understood as the limitation of the patent scope of the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An engineering vehicle drive axle differential structure optimization method, characterized in that, The method comprises the following steps: establishing a main reducer model and a differential model based on a drive axle to be optimized; obtaining an initial load spectrum parameter group based on parameters of the drive axle to be optimized and a first reverse towing working condition; obtaining a first stress cloud map through finite element analysis based on the main reducer model, the differential model and the initial load spectrum parameter group, and extracting a first maximum stress point from the first stress cloud map; updating the differential model to a transition differential model according to the first maximum stress point; extracting a gear parameter group from the parameters of the drive axle to be optimized, calculating a rotating internal friction torque, a sliding internal friction torque, a steering outer side internal friction torque and a steering inner side internal friction torque based on a second reverse towing working condition, the gear parameter group and the initial load spectrum parameter group; obtaining a plurality of updated load working conditions based on the rotating internal friction torque, the sliding internal friction torque, the steering outer side internal friction torque and the steering inner side internal friction torque, adding the plurality of updated load working conditions to the load working conditions corresponding to the initial load spectrum parameter group, and updating the initial load spectrum parameter group to an updated load spectrum parameter group; obtaining a second stress cloud map through finite element analysis based on the main reducer model, the transition differential model and the updated load spectrum parameter group, and extracting a second maximum stress point from the second stress cloud map; updating the transition differential model to a final differential model according to the second maximum stress point.

2. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 1, wherein, The step of establishing the main reducer model and the differential model based on the drive axle to be optimized comprises: establishing a bearing sub-model based on an actual bearing model of the drive axle to be optimized; establishing a bevel gear sub-model using a bevel gear pair command, and performing modification on the bevel gear sub-model based on actual tooth profile parameters of the drive axle to be optimized to obtain a master-slave bevel gear sub-model; establishing the main reducer model based on the bearing sub-model and the master-slave bevel gear sub-model; establishing an initial differential housing model based on an actual state of the drive axle to be optimized, performing mesh division on the initial differential housing model, and setting left housing material and right housing material of the initial differential housing model to obtain a final differential housing model; establishing the differential model based on the final differential housing model and the master-slave bevel gear sub-model.

3. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 1 wherein, The initial load spectrum parameter group comprises input rotation speed, output rotation speed, input torque, output torque, input power, output power, continuous operation time and working temperature.

4. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 1 wherein, The step of updating the differential model to a transition differential model according to the first maximum stress point comprises: positionally comparing the first maximum stress point with the differential model; if the first maximum stress point is located at the left housing of the differential model, increasing the large surface thickness of the left housing of the differential model to obtain a transition differential model; if the first maximum stress point is located at the right housing of the differential model, increasing the first round corner of the right housing of the differential model to obtain a transition differential model.

5. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 1 wherein, The gear parameter set includes a planetary gear pressure angle, a planetary gear pitch angle, a half axle gear pressure angle, a planetary gear and planetary shaft mounting hole radius, a planetary gear spherical surface radius, a planetary gear back spherical surface radius, a half axle gear pitch circle radius, a planetary gear friction coefficient and a half axle gear friction coefficient.

6. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 5, wherein, The formula of the rotation internal friction torque is: wherein, represents the rotational internal friction force, represents the torque transmitted by the differential, represents the pitch circle radius of the half shaft gear, represents the friction coefficient between the planetary gear and the differential housing, represents the spherical radius of the planetary gear, represents the mounting hole radius of the planetary gear to the planetary shaft, represents the pressure angle of the planetary gear, represents the pitch cone angle of the planetary gear, represents the back spherical radius of the planetary gear.

7. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 6 wherein, The formula of the sliding internal friction torque is: wherein, represents the sliding internal friction torque, represents the torque transmitted by the differential, represents the pitch circle radius of the half shaft gear, represents the friction coefficient between the planetary gear and the planetary gear shaft, represents the radius of the mounting hole of the planetary gear and the planetary shaft, represents the pressure angle of the planetary gear, represents the pitch cone angle of the planetary gear.

8. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 7, wherein, The formula of the steering outer internal friction torque is: wherein, represents the turning outboard internal friction moment, represents the friction coefficient between the half shaft gear and the differential housing, represents the torque transmitted by the differential, represents the rotational internal friction, represents the sliding internal friction moment, represents the pitch circle radius of the half shaft gear, represents the planetary gear pressure angle, represents the half shaft gear pressure angle.

9. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 7 wherein, The formula of the steering inner internal friction torque is: wherein, represents the steering inboard internal friction moment, represents the friction coefficient between the half shaft gear and the differential housing, represents the torque transmitted by the differential, represents the rotational internal friction, represents the sliding internal friction moment, represents the pitch radius of the half shaft gear, represents the planetary gear pressure angle, represents the half shaft gear pressure angle.

10. The method of optimizing the construction of an engineering vehicle drive axle differential according to claim 1 wherein, The step of updating the transition differential mechanism model to a final differential mechanism model according to the second maximum stress point includes: Comparing the second maximum stress point with the transition differential mechanism model in position; If the second maximum stress point is located at the left shell of the transition differential mechanism model, reinforcing ribs of the left shell of the transition differential mechanism model are modified to obtain a final differential mechanism model; If the second maximum stress point is located at the right shell of the transition differential mechanism model, a first round corner or a second round corner of the right shell of the transition differential mechanism model is increased to obtain a final differential mechanism model.

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