A system and method for impact simulation durability optimization of a two-gear reduction gearbox shift end point

Abstract

The application discloses a two-gear reduction gearbox shift stop point impact simulation durability optimization system and method, comprising an impact simulation optimization module and an impact durability optimization module; the impact simulation optimization module is used for calculating a stop point contact surface pressure value according to a given shift drum impact speed, and judging whether the stop point contact surface pressure value meets a stop point strength requirement; the impact durability optimization module is used for calculating a total damage value of the shift stop point within a vehicle warranty period according to the given shift drum impact speed, an optimized contact area of the shift stop point impact and a shift stop point structure, and judging whether the total damage value of the shift stop point within the vehicle warranty period meets a service life requirement of the shift stop point. The impact durability optimization system and method designed by the application have the characteristics of standardization, scientificity and implementability, and provide a standardized optimization process for simulation and verification of the impact durability performance of a shift mechanism of a two-gear reduction gearbox.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of simulation and verification of reduction gearbox, in particular to a two-gear reduction gearbox shift stop impact simulation durability optimization system and method. BACKGROUND

[0002] The two-gear reduction gearbox has a shift function, which is realized by the rotation of the shift drum and the reduction gearbox housing. When the reduction gearbox shifts, the shift drum is rotated to move the shift fork in and out of the shift drum groove, thereby realizing the function of shifting.

[0003] By precisely controlling the position of the shift drum, the entire shift process of the reduction gearbox can be precisely controlled. The acquisition of the shift drum position and the accuracy of the shift drum position need to be ensured by the shift stop structure. If the shift stop structure or the strength design is unreasonable, or the software settings for controlling the shift stop self-learning process and the shift stop self-checking process are unreasonable, it may cause the shift stop to be broken, the shell reinforcement near the stop to crack, and the reduction gear of the shift mechanism to break teeth.

[0004] Therefore, for the impact durability performance of the stop points (including the upper functional stop point and the lower functional stop point) of the shift mechanism throughout its entire life cycle, a reasonable and scientific simulation and test method needs to be developed to optimize the stop point structure and precisely control the shift stop point position. SUMMARY

[0005] The purpose of the present application is to solve the above-mentioned problems in the background art, and to provide an impact simulation durability optimization system and method that can identify stop point design risks in advance, optimize test parameters, meet the needs of actual use scenarios, and is easy to implement.

[0006] To achieve this purpose, the impact simulation durability optimization system for the shift stop points of the two-gear reduction gearbox designed by the present application includes an impact simulation optimization module and an impact durability optimization module. The impact simulation optimization module is used to calculate the stop point contact surface pressure value according to the given shift drum impact speed, determine whether the stop point contact surface pressure value meets the stop point strength requirement, and optimize the contact area of the shift stop point impact and the shift stop point structure according to the determination result. The impact durability optimization module is used to calculate the total damage value of the shift stop point within the warranty period of the whole vehicle according to the given shift drum impact speed, the optimized contact area of the shift stop point impact, and the shift stop point structure, determine whether the total damage value of the shift stop point within the warranty period of the whole vehicle meets the service life requirement of the shift stop point, and optimize the shift drum impact speed and the shift stop point structure according to the determination result.

[0007] Further, the impact simulation optimization module comprises an impact torque calculation module, a finite element model construction module and an impact optimization module; the impact torque calculation module is used for calculating the impact torque of the shift stop point according to the given shift drum impact speed; the finite element model construction module is used for constructing the finite element model of the shift drum and the reduction gearbox shell according to the impact torque of the shift stop point, calculating the stop point contact surface pressure value corresponding to the impact torque, and judging whether the stop point contact surface pressure value meets the stop point strength requirement; the impact optimization module is used for optimizing the contact area of the shift stop point impact and the shift stop point structure according to the judgment result of whether the stop point contact surface pressure value meets the stop point strength requirement.

[0008] Further, the impact durability optimization module comprises a fatigue simulation model construction module and a durability optimization module; the fatigue simulation model construction module is used for constructing the fatigue simulation model of the shift drum and the reduction gearbox shell according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the shift stop point structure, calculating the total damage value of the shift stop point within the vehicle warranty period, and judging whether the total damage value of the shift stop point within the vehicle warranty period meets the service life requirement of the shift stop point; the durability optimization module is used for optimizing the shift drum impact speed and the shift stop point structure according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the service life requirement of the shift stop point.

[0009] Further, the impact simulation durability optimization method of the two-shift reduction gearbox shift stop point designed by the present application comprises the following steps: calculating the impact torque of the shift stop point according to the given shift drum impact speed, constructing the finite element model of the shift drum and the reduction gearbox shell according to the impact torque of the shift stop point, calculating the stop point contact surface pressure value corresponding to the impact torque, judging whether the stop point contact surface pressure value meets the stop point strength requirement, and optimizing the contact area of the shift stop point impact and the shift stop point structure according to the judgment result of whether the stop point contact surface pressure value meets the stop point strength requirement; constructing the fatigue simulation model of the shift drum and the reduction gearbox shell according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the shift stop point structure, calculating the total damage value of the shift stop point within the vehicle warranty period, judging whether the total damage value of the shift stop point within the vehicle warranty period meets the service life requirement of the shift stop point, and optimizing the shift drum impact speed and the shift stop point structure according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the service life requirement of the shift stop point.

[0010] Further, the calculation of the impact torque of the shift stop point comprises the calculation of the impact torque of the upper shift stop point in the self-learning working condition and the self-checking working condition and the calculation of the impact torque of the lower shift stop point in the self-learning working condition and the self-checking working condition; the method for calculating the impact torque of the shift stop point is as follows: the shift drum impact speed is brought into the formula of the impact torque of the shift stop point to obtain the impact torque of the shift stop point.

[0011] Further, the method for judging whether the contact surface pressure value of the shift end point meets the strength requirement of the shift end point and optimizing the contact area of the shift end point impact and the structure of the shift end point according to the judging result of whether the contact surface pressure value of the shift end point meets the strength requirement of the shift end point is: comparing the maximum contact surface pressure value corresponding to the maximum impact torque of the shift end point with the limit contact surface pressure value under the shift end point strength requirement of the shift drum and the reduction gearbox shell, if the maximum contact surface pressure value is not higher than the limit contact surface pressure value, the contact area of the shift end point impact and the structure of the shift end point do not need to be optimized; if the maximum contact surface pressure value is higher than the limit contact surface pressure value, the contact area of the shift end point impact and the structure of the shift end point need to be optimized.

[0012] Further, the method for constructing the fatigue simulation model of the shift drum and the reduction gearbox shell according to the given impact speed of the shift drum, the optimized contact area of the shift end point impact and the structure of the shift end point is: based on the optimized contact area of the shift end point impact and the structure of the shift end point, constructing the load spectrum of the shift end point impact durability test working condition of the shift end point in which the self-learning working condition and the self-checking working condition of the shift end point are alternately cycled according to the given impact speed of the shift drum, and constructing the fatigue simulation model of the shift drum and the reduction gearbox shell according to the load spectrum of the shift end point impact durability test working condition.

[0013] Further, the method for calculating the total damage value of the shift end point in the warranty period of the whole vehicle is: obtaining the number n1 of the appearance of the load amplitude of the self-learning working condition of the shift drum at the shift end point position according to the fatigue simulation model of the shift drum and the reduction gearbox shell, querying the S-N curve of the part to obtain the cycle number N1 corresponding to the same load amplitude, obtaining the number n2 of the appearance of the load amplitude of the self-checking working condition of the shift drum at the shift end point position according to the fatigue simulation model of the shift drum and the reduction gearbox shell, and querying the S-N curve of the part to obtain the cycle number N2 corresponding to the same load amplitude, then the total damage value of the shift end point in the warranty period of the whole vehicle is n1 / N1+n2 / N2.

[0014] Further, the method for judging whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point is: if the total damage value of the shift stop point within the vehicle warranty period is not greater than the maximum damage set value, the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point; if the total damage value of the shift stop point within the vehicle warranty period is greater than the maximum damage set value, the total damage value of the shift stop point within the vehicle warranty period does not meet the life requirement of the shift stop point, and the shift drum impact speed needs to be reduced until the total damage value of the shift stop point within the vehicle warranty period is not greater than the maximum damage set value; if the shift drum impact speed is reduced and still cannot meet the life requirement of the shift stop point, the shift stop point structure needs to be re-optimized until the stop point contact surface pressure value and the total damage value of the shift stop point within the vehicle warranty period both meet the standards.

[0015] Still further, the impact simulation durability optimization method for the shift stop point of the two-gear reduction gearbox designed by the application comprises the following steps:

[0016] Step one: calculate the impact torque of the shift stop point according to the given shift drum impact speed;

[0017] Step two: build a finite element model of the shift drum and the reduction gearbox shell according to the impact torque of the shift stop point, calculate the stop point contact surface pressure value corresponding to the impact torque, and judge whether the stop point contact surface pressure value meets the stop point strength requirement;

[0018] Step three: optimize the contact area of the shift stop point impact and the shift stop point structure according to the judgment result of whether the stop point contact surface pressure value meets the stop point strength requirement;

[0019] Step four: build a fatigue simulation model of the shift drum and the reduction gearbox shell according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the shift stop point structure, calculate the total damage value of the shift stop point within the vehicle warranty period, and judge whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point;

[0020] Step five: optimize the shift drum impact speed and the shift stop point structure according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point.

[0021] The beneficial effects of the present application are: the present application establishes corresponding optimization modules and optimization methods for the shift characteristics of the two-gear reduction gearbox, the impact performance and durability of the shift stop point, optimizes the load data and shift stop point structure of the two-gear reduction gearbox through two sets of optimization modules, effectively simulates the shift state of the two-gear reduction gearbox in actual use, and the two-gear reduction gearbox meets the shift impact requirements while having good impact durability. The impact durability optimization system and method designed in the present application have the characteristics of standardization, scientificity and implementability, and provide a standardized optimization process for the simulation and verification of the impact durability of the shift mechanism of the two-gear reduction gearbox. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a module connection diagram of the impact simulation durability optimization system in the present application;

[0023] Figure 2 It is a functional stop point structure perspective view of the reduction gearbox housing in the present application;

[0024] Figure 3 It is a functional stop point structure perspective view of the shift drum in the present application;

[0025] Among them, 1-impact simulation optimization module (1.1-impact torque calculation module, 1.2-finite element model construction module, 1.3-impact optimization module), 2-impact durability optimization module (2.1-fatigue simulation model construction module, 2.2-durability optimization module), 3-reduction gearbox housing, 4-shift drum, 5-reduction gearbox housing upper stop point, 6-reduction gearbox housing lower stop point, 7-shift drum upper stop point, 8-shift drum lower stop point. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0027] As shown in Figure 2 -3, the shift stop point structure is divided into two parts: one part is the reduction gearbox housing upper stop point 5 and the reduction gearbox housing lower stop point 6 structure shown in Figure 2 -4 located on the reduction gearbox housing 3; the other part is the shift drum upper stop point 7 and the shift drum lower stop point 8 shown in Figure 3 -4 located on the shift drum 4.

[0028] After the initial assembly of the reduction gearbox or the loss of the position of the shift drum, at this time the position information of the shift drum upper stop point 7 and the position information of the shift drum lower stop point 8 in the MCU software are invalid, and the shift drum upper stop point 7 and the shift drum lower stop point 8 need to be found again; in addition, after long-term operation of the reduction gearbox, the position accuracy of the shift drum 4 may not meet the use requirements due to the cumulative error of parts and software.

[0029] Therefore, in the whole life cycle of the reduction gearbox, the MCU software needs to perform two important processes: 1. Obtain the position of the shift drum 4, i.e. perform the self-learning process of the shift end point position, and the conditions for triggering the process to run are that the shift drum position is lost or manually triggered, etc. When obtaining the position of the shift drum upper end point 7, the shift drum 4 rotates upward at a given target impact speed Vstudy until the shift drum upper end point 7 hits the reduction gearbox housing upper end point 5, and after hitting the reduction gearbox housing upper end point 5, the impact speed of the shift drum upper end point 7 is reduced to 0° / s, which means that the shift drum upper end point 7 has reached the maximum position of the upward stroke, and at this time the position of the shift drum upper end point 7 is defined as Pup through the self-learning process. When obtaining the position of the shift drum lower end point 8, the shift drum 4 rotates downward at a given target impact speed Vstudy until the shift drum upper and lower end point 8 hits the reduction gearbox housing lower end point 6, and after hitting the reduction gearbox housing lower end point 6, the impact speed of the shift drum upper and lower end point 8 is reduced to 0° / s, which means that the shift drum upper and lower end point 8 has reached the maximum position of the downward stroke, and at this time the position of the shift drum lower end point 8 is defined as Pdown through the self-learning process.

[0030] 2. To ensure the accuracy of the position of the shift drum 4, the self-checking process of the shift end point position needs to be performed, and according to the result of the self-checking, the positions of the shift drum upper end point 7 and the shift drum lower end point 8 are corrected, and the conditions for triggering the process to run are that the vehicle is powered on or other self-checking strategies. When correcting the position of the shift drum upper end point 7, the shift drum 4 rotates upward at a given target impact speed Vcheck until the shift drum upper end point 7 hits the reduction gearbox housing upper end point 5, and after hitting, the impact speed of the shift drum upper end point 7 is reduced to 0° / s, which means that the position of the shift drum upper end point 7 has reached the maximum position of the upward stroke, and at this time the shift drum upper end point 7 is corrected to Pup' through the self-checking process. When correcting the position of the shift drum lower end point 8, the shift drum 4 rotates downward at a given target impact speed Vcheck until the shift drum lower end point 8 hits the reduction gearbox housing lower end point 6, and after hitting, the impact speed of the shift drum lower end point 8 is reduced to 0° / s, which means that the shift drum lower end point 8 has reached the maximum position of the downward stroke, and at this time the position of the shift drum lower end point 8 is corrected to Pdown' through the self-checking process.

[0031] The impact simulation durability optimization system and method for the shift stop point of the two-gear reduction gearbox designed by the application comprises formulating the impact speed Vstudy corresponding to the stop point position self-learning working condition, the self-learning operation number Nstudy, the impact speed Vcheck corresponding to the stop point position self-checking working condition and the self-checking working condition operation number Ncheck, inputting the load spectrum of the self-learning and self-checking working conditions into the finite element model for analysis, optimizing the impact speed, so that the simulation impact life of the shift mechanism meets the actual use requirements. Finally, the self-learning working condition and the self-checking working condition can be measured and tested on the two-gear reduction gearbox according to the optimized parameters, and the shift mechanism stop point impact durability is verified. The impact simulation durability optimization system and method for the shift stop point of the two-gear reduction gearbox designed by the application can identify the stop point design risk and the test parameter risk in advance, and optimize the structure and the test parameters.

[0032] To achieve the purpose of identifying the stop point design risk and the test parameter risk in advance and optimizing the structure and the test parameters, the application designs Figure 1 The impact simulation durability optimization system for the shift stop point of the two-gear reduction gearbox shown in the figure comprises an impact simulation optimization module 1 and an impact durability optimization module 2.

[0033] The impact simulation optimization module 1 is used to calculate the stop point contact surface pressure value according to the given shift drum impact speed, judge whether the stop point contact surface pressure value meets the stop point strength requirement, and optimize the contact area of the shift stop point impact and the shift stop point structure according to the judgment result. The impact simulation optimization module 1 comprises an impact torque calculation module 1.1, a finite element model construction module 1.2 and an impact optimization module 1.3. The impact torque calculation module 1.1 is used to calculate the impact torque of the shift stop point according to the given shift drum impact speed; the finite element model construction module 1.2 is used to construct the finite element model of the shift drum and the reduction gearbox shell according to the impact torque of the shift stop point, calculate the stop point contact surface pressure value corresponding to the impact torque, and judge whether the stop point contact surface pressure value meets the stop point strength requirement; the impact optimization module 1.3 is used to optimize the contact area of the shift stop point impact and the shift stop point structure according to the judgment result of whether the stop point contact surface pressure value meets the stop point strength requirement.

[0034] The impact durability optimization module 2 is used to calculate the total damage value of the shift stop point within the vehicle warranty period according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the shift stop point structure, judge whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point, and optimize the shift drum impact speed and the shift stop point structure according to the judgment result. The impact durability optimization module 2 comprises a fatigue simulation model construction module 2.1 and a durability optimization module 2.2. The fatigue simulation model construction module 2.1 is used to construct the fatigue simulation model of the shift drum and the reduction gearbox shell according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the shift stop point structure, calculate the total damage value of the shift stop point within the vehicle warranty period, and judge whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point; the durability optimization module 2.2 is used to optimize the shift drum impact speed and the shift stop point structure according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point.

[0035] Based on the impact simulation durability optimization system of the two-gear reduction gearbox shift stop point, the impact simulation durability optimization method of the two-gear reduction gearbox shift stop point designed by the application comprises the following steps:

[0036] Step one: calculate the impact torque of the shift stop point according to the given shift drum impact speed, including calculating the impact torque of the upper stop point of the shift drum under the self-learning working condition and the self-checking working condition and calculating the impact torque of the lower stop point of the shift drum under the self-learning working condition and the self-checking working condition. According to the kinematics model, the calculation formula of the stop point impact torque is: T = γ * V; wherein T: the impact torque corresponding to the impact speed V; γ: the conversion coefficient, which is calculated according to the dynamics model; V: the impact speed. Therefore, the shift drum impact speed is brought into the formula of the impact torque of the shift stop point, and the impact torque of the shift stop point can be obtained.

[0037] Step two: construct the finite element model of the shift drum and the reduction gearbox shell according to the impact torque of the shift stop point, calculate the stop point contact surface pressure value corresponding to the impact torque, and judge whether the stop point contact surface pressure value meets the stop point strength requirement. The method is: compare the maximum stop point contact surface pressure value corresponding to the maximum impact torque of the shift stop point with the limit contact surface pressure value under the shift stop point strength requirement of the shift drum and the reduction gearbox shell. If the maximum stop point contact surface pressure value is not higher than the limit contact surface pressure value, the contact area of the shift stop point impact and the shift stop point structure do not need to be optimized; if the maximum stop point contact surface pressure value is higher than the limit contact surface pressure value, the contact area of the shift stop point impact and the shift stop point structure need to be optimized.

[0038] Step three: according to the judgment result of whether the contact surface pressure value of the shift stop meets the requirement of the shift stop strength, the contact area of the shift stop impact and the structure of the shift stop are optimized, the method is: based on the optimized contact area of the shift stop impact and the structure of the shift stop, according to the given shift drum impact speed, the load spectrum of the shift stop impact durability test working condition of the self-learning working condition and the self-checking working condition of the shift stop are alternately circulated in the whole vehicle warranty period, and the fatigue simulation model of the shift drum and the reduction gearbox shell is constructed. The method of formulating the shift stop impact durability test load spectrum of the two-gear reduction gearbox is as follows:

[0039] The shift stop impact durability test is divided into the following four steps: (1) self-learning working condition, the cycle number of upper and lower stop position self-learning is Nstudy / 2, and the corresponding target impact speed is Vstudy. (2) driving stop self-checking working condition, the cycle number of upper and lower stop position self-checking is Ncheck / 2, and the corresponding target impact speed is Vcheck. (3) repeat the self-learning working condition of (1). (4) repeat the driving self-checking working condition of (2). The self-learning working condition and the driving stop self-checking working condition are alternately run, which can maximize the simulation of the actual use. In the whole life cycle of the reduction gearbox, the two working conditions are often alternately run.

[0040] The following table is a schematic table of the shift stop impact durability test working condition:

[0041]

[0042]

[0043] The number of shift stop self-learning needs to consider the self-learning number in the reduction gearbox factory test or the off-line process, the self-learning number in the vehicle factory test or the off-line process, and the self-learning number when troubleshooting after sale. Considering the above three application scenarios, the total number of shift stop self-learning is: Nstudy=(ntm+nvh+nwa)*α. Wherein, Nstudy: the total number of shift stop self-learning in the whole warranty period; ntm: the number of self-learning in the reduction gearbox factory test or the off-line process (take the most stringent case); nvh: the number of self-learning in the vehicle factory test or the off-line process (take the most stringent case); nwa: the number of self-learning when troubleshooting after sale (take the most stringent case); α: self-learning working condition verification coefficient, greater than 1 (set according to the requirement of reliability).

[0044] During the whole life cycle of the vehicle, the position of the shift end point will have a certain cumulative error over time, and the main sources of error are: slight wear of hardware, system cumulative error and other factors. In order to ensure the accuracy of the shift stroke and gear position, the position of the shift end point needs to be self-checked. If the result of the self-checking shows that the error of the end point position is too large, the end point position needs to be further corrected. The conditions for starting the shift end point self-checking event are generally that the vehicle self-checks once after each power-on, the warranty period of the vehicle is Y years, and the most severe customer is predicted to power on and off n times per day on average, and the total number of self-checks during the warranty period is: Ncheck=Y*365*ncus*β. Wherein: Ncheck: the total number of shift end point self-checks during the warranty period; Y: warranty period of the vehicle; ncus: the number of power-on and power-off of the most severe customer per day on average; β: self-checking condition verification coefficient, greater than 1, set according to the requirement of reliability.

[0045] Since the positions of the upper and lower end points of the shift drum during the driving self-checking process are determinable, when establishing the load spectrum of the shift end point impact durability test condition, only the position information of the upper and lower end points of the shift drum during the driving self-checking is needed to be input. As for the self-learning condition, since the starting point of each self-learning cannot be determined, it is necessary to comprehensively cover all the shift self-learning end point positions, maximize the simulation of real vehicle conditions. Since the starting point of each self-learning is different, it is necessary to include the entire shift stroke from Pstart(the position of the lower end point of the shift drum) to Pend(the position of the upper end point of the shift drum), and the shift stroke step is set to S, then the shift drum self-learning starting point position is: Nstep=(Pend-Pstart) / S|rounded up; Pstudy|n=1:Nstep=Pstart+(n-1)*S; Np=Nstudy / Nstep|rounded up. Wherein, Pstudy|n=1:Nstep: the shift drum self-learning starting point position covered in a shift stroke; Np: the number of self-learning processes at the same shift drum self-learning starting point position.

[0046] Step four: according to the given shift drum impact speed, the optimized contact area of the shift end point impact and the structure of the shift end point, the fatigue simulation model of the shift drum and the reduction box shell is constructed, the total damage value of the shift end point in the vehicle warranty period is calculated, and whether the total damage value of the shift end point in the vehicle warranty period meets the life requirement of the shift end point is judged; the method is: according to the fatigue simulation model of the shift drum and the reduction box shell, the number n1 of the self-learning working condition load amplitude of the shift drum at the end point position is obtained, the S-N curve of the part is queried, and the corresponding cycle number N1 of the same load amplitude is obtained; according to the fatigue simulation model of the shift drum and the reduction box shell, the number n2 of the self-checking working condition load amplitude of the shift drum at the end point position is obtained, the S-N curve of the part is queried, and the corresponding cycle number N2 of the same load amplitude is obtained, then the total damage value of the shift end point in the vehicle warranty period is n1 / N1+n2 / N2.

[0047] Step five: according to the judgment result of whether the total damage value of the shift end point in the vehicle warranty period meets the life requirement of the shift end point, the shift drum impact speed and the shift end point structure are optimized; whether the total damage value of the shift end point in the vehicle warranty period meets the life requirement of the shift end point is judged, and the method is: if the total damage value of the shift end point in the vehicle warranty period is not greater than 1, the total damage value of the shift end point in the vehicle warranty period meets the life requirement of the shift end point, if the total damage value of the shift end point in the vehicle warranty period is greater than 1, the total damage value of the shift end point in the vehicle warranty period does not meet the life requirement of the shift end point, the shift drum impact speed needs to be reduced until the total damage value of the shift end point in the vehicle warranty period is not greater than the maximum damage set value, if the shift drum impact speed is reduced and still cannot meet the life requirement of the shift end point, the structure of the shift end point needs to be optimized again until the contact surface pressure value of the end point and the total damage value of the shift end point in the vehicle warranty period are up to standard.

[0048] The following table is a schematic table of the optimized shift end point impact durability test condition:

[0049]

[0050] Among them, Vs: the optimized self-learning impact speed; Vc: the optimized driving end point self-checking impact speed.

[0051] After obtaining the above-mentioned optimized load spectrum, the test can be carried out according to the above-mentioned optimized load spectrum, that is, the wire harness and MCU of the electric drive assembly are mounted, so as to realize the verification of the hardware structure of the shift end point and the verification of the software function of the wire harness and MCU. During the test, the actual value of the shift drum impact speed is not more than ±20% of the target value, which is qualified.

[0052] The application is aimed at a shift structure of a two-gear reduction gearbox, and impact simulation optimization module 1 for meeting the shift impact performance and impact durability optimization module 2 for meeting the shift durability performance are designed. The shift structure of the two-gear reduction gearbox optimized by the impact simulation optimization module 1 and the impact durability optimization module 2 can meet the requirements of the shift impact performance and the shift durability performance at the same time, and the stability of the shift structure and function of the two-gear reduction gearbox in the warranty period is ensured.

[0053] The impact simulation optimization module 1 includes three sub-modules, impact torque calculation module 1.1, finite element model construction module 1.2 and impact optimization module 1.3, which can calculate the impact torque of the shift stop point based on the shift drum impact speed, construct the finite element model of the shift drum and the reduction gearbox shell by using Abaqus, Femfat and other software according to the impact torque of the shift stop point, calculate the stop point contact surface pressure value corresponding to the impact torque (the pressure value generated between the shift drum stop point and the reduction gearbox shell stop point when the shift drum impact speed drops to 0), compare the maximum stop point contact surface pressure value with the limit contact surface pressure value meeting the strength requirements of the shift stop point of the shift drum and the reduction gearbox shell, if the maximum stop point contact surface pressure value is not higher than the limit contact surface pressure value, the contact area of the shift stop point impact and the shift stop point structure do not need to be optimized, and if the maximum stop point contact surface pressure value is higher than the limit contact surface pressure value, the contact area of the shift stop point impact and the shift stop point structure need to be optimized, for example, the contact area of the shift stop point impact can be increased or the stop point radius can be increased or the structural strength of the shift stop point can be increased, such as adding reinforcing ribs at the shift stop point. The optimization by the impact simulation optimization module 1 can ensure that the shift structure and the shift speed meet the design requirements.

[0054] The impact durability optimization module 2 includes two sub-modules, fatigue simulation model construction module 2.1 and durability optimization module 2.2, which can construct the fatigue simulation model of the shift drum and the reduction gearbox shell by using Abaqus, Femfat and other software based on the given shift drum impact speed, the optimized contact area of the shift stop point impact and the shift stop point structure, calculate the total damage value of the shift stop point within the warranty period of the whole vehicle, compare the total damage value of the shift stop point within the warranty period of the whole vehicle with the maximum damage setting value (set to 1 in this embodiment), if the total damage value of the shift stop point within the warranty period of the whole vehicle is greater than the maximum damage setting value, the total damage value of the shift stop point within the warranty period of the whole vehicle does not meet the life requirements of the shift stop point, the shift drum impact speed needs to be reduced until the total damage value of the shift stop point within the warranty period of the whole vehicle is not greater than the maximum damage setting value, and if the shift drum impact speed is reduced and still cannot meet the life requirements of the shift stop point, the shift stop point structure needs to be re-optimized (such as increasing the contact area between the shift stop points, reducing the stress concentration, etc.), until the stop point contact surface pressure value and the total damage value of the shift stop point within the warranty period of the whole vehicle are up to standard.

[0055] To sum up, the application establishes corresponding optimization modules and optimization methods for the shift characteristics of the two-gear reduction gearbox, the impact performance and the durability of the shift stop point, and the load data and the shift stop point structure of the two-gear reduction gearbox are optimized through two groups of optimization modules, so that the shift state of the two-gear reduction gearbox in actual use is effectively simulated, the two-gear reduction gearbox meets the shift impact requirements, and has good impact durability. The impact durability optimization system and method designed in the application have the characteristics of standardization, scientificity and implementability, and provide a standardized optimization process for the simulation and verification of the impact durability of the shift mechanism of the two-gear reduction gearbox.

[0056] The above is only a preferred embodiment of the application, and does not limit the structure of the application in any form. Any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the application still belongs to the scope of the technical solution of the application.

Claims

1. A two-gear reduction gearbox shift end point impact simulation durability optimization system, characterized in that: It includes impact simulation optimization module (1) and impact durability optimization module (2); The impact simulation optimization module (1) is used for calculating the contact surface pressure value of the stop point according to the given shift drum impact speed, judging whether the contact surface pressure value of the stop point meets the strength requirement of the stop point, and optimizing the contact area of the shift stop point impact and the structure of the shift stop point according to the judgment result; The impact durability optimization module (2) is used for calculating the total damage value of the shift stop point within the vehicle warranty period according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the structure of the shift stop point, judging whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point, and optimizing the shift drum impact speed and the structure of the shift stop point according to the judgment result; The impact simulation optimization module (1) includes impact torque calculation module (1.1), finite element model construction module (1.2) and impact optimization module (1.3); The impact torque calculation module (1.1) is used for calculating the impact torque of the shift stop point according to the given shift drum impact speed; The finite element model construction module (1.2) is used for constructing the finite element model of the shift drum and the reduction gearbox shell according to the impact torque of the shift stop point, calculating the contact surface pressure value corresponding to the impact torque, and judging whether the contact surface pressure value meets the strength requirement of the stop point; The impact optimization module (1.3) is used for optimizing the contact area of the shift stop point impact and the structure of the shift stop point according to the judgment result of whether the contact surface pressure value meets the strength requirement of the stop point.

2. The impact emulation durability optimization system for shift end points of a two-speed reduction gearbox according to claim 1, characterized in that: The impact durability optimization module (2) includes fatigue simulation model construction module (2.1) and durability optimization module (2.2); The fatigue simulation model construction module (2.1) is used for constructing the fatigue simulation model of the shift drum and the reduction gearbox shell according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the structure of the shift stop point, calculating the total damage value of the shift stop point within the vehicle warranty period, and judging whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point; The durability optimization module (2.2) is used for optimizing the shift drum impact speed and the structure of the shift stop point according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point.

3. A method for impact simulation durability optimization of shift end point of a two-gear reduction gearbox, characterized in that: According to the given shift drum impact speed, the impact torque of the shift stop point is calculated, the finite element model of the shift drum and the reduction gearbox shell is constructed according to the impact torque of the shift stop point, the contact surface pressure value corresponding to the impact torque is calculated, it is judged whether the contact surface pressure value meets the strength requirement of the stop point, and the contact area of the shift stop point impact and the structure of the shift stop point are optimized according to the judgment result of whether the contact surface pressure value meets the strength requirement of the stop point. According to the given shift drum impact speed, the contact area of the optimized shift stop point impact and the structure of the shift stop point, a fatigue simulation model of the shift drum and the reduction gearbox shell is constructed, the total damage value of the shift stop point within the vehicle warranty period is calculated, whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point is judged, and the shift drum impact speed and the shift stop point structure are optimized according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point. The method for judging whether the contact surface pressure value of the shift stop point meets the strength requirement of the shift stop point and optimizing the contact area of the shift stop point impact and the structure of the shift stop point according to the judgment result of whether the contact surface pressure value of the shift stop point meets the strength requirement of the shift stop point is: comparing the maximum contact surface pressure value of the shift stop point corresponding to the maximum impact torque with the limit contact surface pressure value meeting the strength requirement of the shift stop point of the shift drum and the reduction gearbox shell, if the maximum contact surface pressure value is not higher than the limit contact surface pressure value, the contact area of the shift stop point impact and the structure of the shift stop point do not need to be optimized, and if the maximum contact surface pressure value is higher than the limit contact surface pressure value, the contact area of the shift stop point impact and the structure of the shift stop point need to be optimized.

4. The method of claim 3, wherein: The method for calculating the impact torque of the shift stop point includes calculating the impact torque of the shift stop point on the shift drum in the self-learning working condition and the self-checking working condition and calculating the impact torque of the shift stop point on the shift drum in the self-learning working condition and the self-checking working condition; the method for calculating the impact torque of the shift stop point is: bringing the shift drum impact speed into the formula of the impact torque of the shift stop point to obtain the impact torque of the shift stop point.

5. The method of claim 4, wherein: The method for constructing the fatigue simulation model of the shift drum and the reduction gearbox shell according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the structure of the shift stop point is: based on the optimized contact area of the shift stop point impact and the structure of the shift stop point, constructing the load spectrum of the shift stop point impact durability test working condition in which the self-learning working condition and the self-checking working condition of the shift stop point within the vehicle warranty period are alternately circulated according to the given shift drum impact speed, and constructing the fatigue simulation model of the shift drum and the reduction gearbox shell according to the load spectrum of the shift stop point impact durability test working condition.

6. The method for impact emulation durability optimization of shift end points of a two-speed reduction gearbox according to claim 5, characterized in that: The method for calculating the total damage value of the shift stop point within the vehicle warranty period is: obtaining the number n1 of the load amplitude of the shift drum in the self-learning working condition at the shift stop point position according to the fatigue simulation model of the shift drum and the reduction gearbox shell, querying the S-N curve of the part to obtain the cycle number N1 corresponding to the same load amplitude, obtaining the number n2 of the load amplitude of the shift drum in the self-checking working condition at the shift stop point position according to the fatigue simulation model of the shift drum and the reduction gearbox shell, and querying the S-N curve of the part to obtain the cycle number N2 corresponding to the same load amplitude, so that the total damage value of the shift stop point within the vehicle warranty period is n1 / N1+n2 / N2.

7. The method for impact emulation durability optimization of shift end points of a two-speed reduction gearbox according to claim 6, characterized in that: The method for judging whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point, and optimizing the shift drum impact speed and the shift stop point structure according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point is: if the total damage value of the shift stop point within the vehicle warranty period is not greater than the maximum damage set value, the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point; if the total damage value of the shift stop point within the vehicle warranty period is greater than the maximum damage set value, the total damage value of the shift stop point within the vehicle warranty period does not meet the life requirement of the shift stop point, and the shift drum impact speed needs to be reduced until the total damage value of the shift stop point within the vehicle warranty period is not greater than the maximum damage set value; if the shift drum impact speed is reduced and still cannot meet the life requirement of the shift stop point, the shift stop point structure needs to be re-optimized until the stop point contact surface pressure value and the total damage value of the shift stop point within the vehicle warranty period both meet the standards.

8. The method of impact emulation durability optimization of shift end points of a two- speed reduction gearbox according to claim 7, characterized in that: The method comprises the following steps: Step one: calculate the impact torque of the shift stop point according to the given shift drum impact speed; Step two: construct a finite element model of the shift drum and the reduction gearbox shell according to the impact torque of the shift stop point, calculate the stop point contact surface pressure value corresponding to the impact torque, and judge whether the stop point contact surface pressure value meets the stop point strength requirement; Step three: optimize the contact area of the shift stop point impact and the shift stop point structure according to the judgment result of whether the stop point contact surface pressure value meets the stop point strength requirement; Step four: construct a fatigue simulation model of the shift drum and the reduction gearbox shell according to the given shift drum impact speed, the optimized contact area of the shift stop point impact and the shift stop point structure, calculate the total damage value of the shift stop point within the vehicle warranty period, and judge whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point; Step five: optimize the shift drum impact speed and the shift stop point structure according to the judgment result of whether the total damage value of the shift stop point within the vehicle warranty period meets the life requirement of the shift stop point.

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