Design method and device for eliminating knocking noise of speed reducer of electric vehicle

Abstract

The invention relates to the technical field of automobiles, in particular to a design method and device for eliminating knocking noise of a speed reducer of an electric vehicle, and the method comprises the steps: firstly, setting the matching relation between the inertias of a motor rotor, an input shaft, an intermediate shaft and a differential mechanism and between a first-stage speed ratio and a second-stage speed ratio; secondly, gear macroscopic parameters are designed based on the matching relation; then, establishing a speed reducer system dynamic model, applying a real wheel end impact load for simulation, and extracting key data such as an angular acceleration peak value, a knocking section angular acceleration root-mean-square value and an impact torque; and finally, by comparing the data of the optimization scheme, the initial scheme and the competitive product, evaluating an optimization effect and performing iteration until a preset target is met. The knocking noise problem is solved in advance in a virtual environment, a prototype does not need to be manufactured, and the cost and the research and development period are remarkably saved; through system-level inertia and speed ratio matching, the NVH performance is optimized from the source, the effect is remarkable, and the method is suitable for various electric drive vehicle types.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and in particular to a design method and apparatus for eliminating knocking noise from the gearbox of an electric vehicle. Background Technology

[0002] When an electric vehicle travels over uneven surfaces such as speed bumps, seams, and potholes, the impact load from the road surface is transmitted to the reducer through the wheels. This drastic change in torque and speed forces the reducer's input shaft, intermediate shaft, and differential (collectively known as the "three shafts") to produce intense angular acceleration fluctuations. When these fluctuations overcome the tooth backlash, abnormal impacts occur between the gears, resulting in knocking noise.

[0003] Currently, there are three major technical challenges in the design process of solving the knocking noise problem in electric drive gearboxes: Key parameter identification is difficult: There are many parameters that affect the striking, including the moment of inertia and stiffness of each shaft, gear parameters (number of teeth, module, etc.) and shaft mating parameters (speed ratio, tooth backlash, etc.). There is a lack of readily available standards to identify the key parameters that have a significant impact on the striking.

[0004] Parameter matching optimization is difficult: After identifying key parameters, there is a lack of clear design guidelines on how to match these parameters (such as inertia ratio and speed ratio) to suppress impact while taking into account the fatigue life and cost of the parts.

[0005] The evaluation indicators are difficult to apply: the knocking evaluation indicators proposed in the industry are mostly applicable to specific structures and scenarios, and lack universality, making it difficult to effectively evaluate and compare the design effects.

[0006] Existing technologies mostly rely on prototyping prototypes and conducting real-vehicle tests using single methods such as adjusting tooth backlash. This approach has limited improvement effects and is costly and time-consuming. Summary of the Invention

[0007] This invention provides a design method and device for eliminating knocking noise in electric vehicle reducers. By setting clear targets for the three-axis inertia ratio and the two-stage speed ratio, an accurate simulation model is established, and through iterative optimization, the knocking noise problem of the reducer can be effectively predicted and solved during the design stage.

[0008] This specification provides an embodiment of a design method for eliminating knocking noise from an electric vehicle's speed reducer, including: Set the ratio relationships between the motor rotor inertia, input shaft inertia, intermediate shaft inertia, differential inertia, first-stage speed ratio, and second-stage speed ratio; and design the macroscopic parameters of the reducer gears based on the set ratio relationships. Build a dynamic model of the reducer system that includes the macroscopic parameters, apply a wheel-end impact load for simulation, and extract simulation result data related to the knocking noise; wherein, the simulation result data at least includes the peak angular acceleration of at least one of the input shaft, the intermediate shaft, and the differential, the root mean square value of the angular acceleration in the knocking section, and the impact torque. Compare the simulation result data with the corresponding data of the initial knocking vehicle model. If at least one of the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section, and the impact torque does not achieve the preset optimization goal compared with the initial knocking vehicle model, then return the ratio relationship between the set motor rotor inertia, input shaft inertia, intermediate shaft inertia, differential inertia, first-stage speed ratio, and second-stage speed ratio until the simulation result data meets the preset optimization goal.

[0009] Optionally, define the total speed ratio i0 as the product of the first-stage speed ratio i1 and the second-stage speed ratio i2, and the ratio relationship includes the speed ratio ratio: When 8 < i0 < 13, i2 / i1 = 1.100 - 1.300; When 6 < i0 < 8, i2 / i1 = 1.200 - 1.400.

[0010] Optionally, the ratio relationship includes the inertia ratio, and the inertia ratio includes: The ratio of the differential inertia J3 to the intermediate shaft inertia J2, J3 / J2 = 5 - 11; The ratio of the motor rotor inertia J0 to the input shaft inertia J0, J0 / J0 = 55 - 110.

[0011] Optionally, the macroscopic parameters of the reducer gear include at least one of the number of teeth, module, pressure angle, helix angle, helix direction, tooth width, and modification coefficient.

[0012] Optionally, the preset optimization goal is that at least one of the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section, and the impact torque is at least 30% lower compared with the initial knocking vehicle model.

[0013] Optionally, the preset optimization goal further includes that at least one of the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section, and the impact torque is less than the corresponding data of a competing product non-knocking vehicle model for comparison.

[0014] Optionally, the wheel-end impact load is the wheel-end torque data under the actual rough road surface collected by a six-component force measuring instrument.

[0015] This embodiment of the specification also provides a design device for eliminating the knocking noise of an electric vehicle reducer, including: The parameter setting module is used to set the ratio relationship between the motor rotor inertia, input shaft inertia, intermediate shaft inertia, differential inertia, first-stage speed ratio, and second-stage speed ratio; and to design the macroscopic parameters of the reducer gears based on the set ratio relationship. The simulation module is used to establish a dynamic model of the reducer system containing the macroscopic parameters, apply wheel-end impact loads for simulation, and extract simulation result data related to the impact noise; wherein, the simulation result data includes at least the peak value of angular acceleration, the root mean square value of angular acceleration of the impact section, and the impact torque of at least one shaft among the input shaft, intermediate shaft, and differential. The data comparison module is used to compare the simulation result data with the corresponding data of the initial impact vehicle model. If at least one of the peak angular acceleration, root mean square value of the impact segment angular acceleration, and impact torque fails to achieve the preset optimization target compared to the initial impact vehicle model, the module returns to the setting of the ratio relationship between the motor rotor inertia, input shaft inertia, intermediate shaft inertia, differential inertia, first-stage speed ratio, and second-stage speed ratio until the simulation result data meets the preset optimization target.

[0016] An electronic device includes a memory and a processor, the memory storing computer instructions, and the processor being configured to execute the computer instructions to perform the method described above.

[0017] A storage medium, characterized in that the storage medium stores computer instructions, the computer instructions being configured to execute the method described above at runtime.

[0018] Its beneficial effects are as follows: By proposing core inertia and speed ratio matching criteria and establishing a precise simulation process, this application can effectively solve the knocking problem in a virtual environment without physical prototypes, significantly saving prototype costs and R&D time; Unlike the traditional method of only adjusting tooth backlash, this application starts from the root of system dynamics (inertia and speed ratio) to perform parameter matching, which has a more fundamental and significant effect on suppressing knocking noise; At the same time, it provides a quantitative matching range and clear simulation evaluation standards (the total knocking evaluation index must be reduced by more than 30% and be better than the competition), making the design process based on evidence and making scientific decisions. It is suitable for solving knocking noise caused by different excitation sources such as bumpy roads or zero-crossing torque of drive motors, and can be widely used in the NVH performance development of reducers for various electric drive models such as PHEV, REEV, and EV. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1A schematic diagram illustrating the principle of a design method for eliminating knocking noise from an electric vehicle reducer, provided in the embodiments of this specification. Figure 2 A schematic diagram of a design device for eliminating knocking noise from an electric vehicle reducer, provided in an embodiment of this specification; Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this specification; Figure 4 This is a schematic diagram of a computer-readable medium provided for embodiments of this specification. Detailed Implementation

[0020] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0022] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0023] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0024] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0026] Reference Figure 1Schematic diagram of the principle of a design method for eliminating the knocking noise of an electric vehicle reducer. The compressor is connected to the vehicle body through multiple mounts, including: S101: Set the ratio relationship among the inertia of the motor rotor, the inertia of the input shaft, the inertia of the intermediate shaft, the inertia of the differential, the first-stage speed ratio, and the second-stage speed ratio; and based on the set ratio relationship, design the macroscopic parameters of the reducer gears; S102: Establish a dynamic model of the reducer system including the macroscopic parameters, apply a wheel-end impact load for simulation, and extract the simulation result data related to the knocking noise; where the simulation result data at least includes the peak angular acceleration of at least one of the input shaft, the intermediate shaft, and the differential, the root mean square value of the angular acceleration in the knocking section, and the impact torque; S103: Compare the simulation result data with the corresponding data of the initial knocking vehicle model. If at least one of the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section, and the impact torque does not achieve the preset optimization goal compared with the initial knocking vehicle model, then return to set the ratio relationship among the inertia of the motor rotor, the inertia of the input shaft, the inertia of the intermediate shaft, the inertia of the differential, the first-stage speed ratio, and the second-stage speed ratio until the simulation result data meets the preset optimization goal.

[0027] The core of this application lies in a systematic "setting - design - simulation - iteration" closed-loop process. First, in the conceptual design stage, that is, set the ratio relationship among the inertia of the motor rotor, the input shaft, the intermediate shaft, and the differential, as well as between the first-stage and second-stage speed ratios, laying a scientific dynamic foundation for the entire design. Then, based on this ratio, conduct specific design of the macroscopic parameters of the gears, transforming the theoretical relationship into manufacturable engineering drawings. Next, establish a high-fidelity system dynamic model and apply a real wheel-end impact load for simulation, accurately extracting the key simulation result data such as the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section, and the impact torque. Finally, evaluate the optimization effect by comparing the data of the improved plan with that of the initial plan. If not up to standard, return to adjust the ratio for iteration. It realizes "design-guided optimization" rather than the traditional "trial and error". By completing multiple iterations in the computer, it fundamentally avoids the high cost and long cycle of blindly making prototypes, and realizes the prior solution of the reducer knocking noise problem at the drawing stage. [

[0028] [ Optionally, define the total speed ratio i0 as the product of the first-stage speed ratio i1 and the second-stage speed ratio i2. The ratio relationship includes speed ratio matching: when 8 < i0 < 13, i2 / i1 = 1.100 - 1.300; when 6 < i0 < 8, i2 / i1 = 1.200 - 1.400. [

[0029] [In an alternative embodiment, different optimization intervals are set according to different application scenarios of the overall reduction ratio i0 of the reducer. For example, for a certain electric vehicle reducer with an overall reduction ratio i0 = 9.5, since it satisfies 8 < i0 < 13, the ratio of the second-stage reduction ratio to the first-stage reduction ratio, i2 / i1 = 1.200, is set. By distributing the overall reduction ratio to the first-stage reduction ratio and the second-stage reduction ratio in a specific proportion, the transmission path of torque and speed in the transmission chain can be optimized, effectively balancing the loads of each shaft system, thereby suppressing the severe fluctuations in the angular acceleration of the shaft system caused by sudden load changes from the source of transmission, which is the key prerequisite for reducing the knocking risk.

[0030] Optionally, the ratio relationship includes an inertia ratio, and the inertia ratio includes: the ratio of the differential inertia J3 to the intermediate shaft inertia J2, J3 / J2 = 5 - 11; the ratio of the motor rotor inertia J0 to the input shaft inertia J0, J0 / J0 = 55 - 110.

[0031] In an alternative embodiment, the ratio of the differential inertia J3 to the intermediate shaft inertia J2 is further set, for example, J3 / J2 = 8; the ratio of the motor rotor inertia J0 to the input shaft inertia J1 is also set, for example, J0 / J1 = 80.

[0032] By controlling the inertia ratio between the downstream (differential) and the midstream (intermediate shaft), it is possible to avoid the system response being sluggish due to excessive differential inertia or insufficient stability due to too small inertia, thereby effectively attenuating the impact energy transmitted from the wheel end to the gear meshing point and reducing the possibility of the gear disengaging and hitting again; and by controlling the inertia relationship between the driving end (motor rotor) and the first transmission shaft (input shaft), it is possible to suppress the direct impact of motor torque fluctuations on the transmission chain and provide a stable input boundary for the entire transmission system.

[0033] Optionally, the macroscopic parameters of the reducer gears include at least one of the number of teeth, module, pressure angle, helix angle, helix direction, tooth width, and modification coefficient.

[0034] For example, to meet the aforementioned inertia and reduction ratio requirements, the module of the first-stage gear pair is designed to be 2.5, and the helix angle is 15°. The modification coefficient is adjusted to ensure the requirements of contact ratio and strength. Transforming the abstract ratio relationship into specific and machinable gear attributes ensures that the system-level dynamic ratio relationship verified as optimal through simulation can be accurately materialized and embodied in the final gear product, guaranteeing the consistency between theoretical design and engineering practice.

[0035] Optionally, the preset optimization goal is that at least one of the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section, and the impact torque is reduced by at least 30% compared to the initial knocking vehicle model.

[0036] For example, simulation results show that the peak angular acceleration of the intermediate shaft decreased from 15,000 rad / s² to 9,000 rad / s² after optimization, a reduction of 40%, thus meeting the preset optimization target. The subjective auditory perception of "improving the impact" is transformed into a precisely measurable engineering indicator such as "angular acceleration reduced by at least 30%." This makes design decisions based on evidence, avoids biases from subjective judgment, and significantly improves optimization efficiency and the reliability of results.

[0037] Optionally, the preset optimization target may also include at least one of the peak angular acceleration, the root mean square value of the angular acceleration of the impact segment, and the impact torque being less than the corresponding data of the competing non-impact vehicle model.

[0038] For example, the simulation results show an impact torque of 280 Nm, which is not only 38% lower than its initial state (450 Nm) but also lower than the 300 Nm of competing models. Therefore, the simulation results meet the preset optimization target. External benchmarks were introduced for comparison, and higher optimization targets were set, requiring not only self-improvement but also market leadership. This ensures that the final design not only solves the problem but also possesses strong market competitiveness, bringing significant NVH performance advantages to the product.

[0039] Optionally, the wheel-end impact load is the wheel-end torque data under actual bumpy road conditions collected by a six-component force measuring instrument.

[0040] In one optional embodiment, the applied wheel-end impact load is not a standard load spectrum, but rather real torque-time data collected using a six-component force measuring instrument on rough road surfaces (such as speed bumps and jointed roads) frequently experienced by actual target users. This emphasizes the realism of the simulation input, making the simulation environment as close as possible to the user's actual usage scenario, thereby ensuring the accuracy and effectiveness of the simulation results. Optimized designs based on these results can accurately solve the knocking noise problem encountered by users in actual driving, greatly improving user satisfaction and market fit of the product.

[0041] Reference Figure 2 This specification also provides a structural diagram of a design device for eliminating knocking noise from an electric vehicle's speed reducer, comprising: The parameter setting module 201 is used to set the ratio relationship between the motor rotor inertia, input shaft inertia, intermediate shaft inertia, differential inertia, first-stage speed ratio, and second-stage speed ratio; and to design the macroscopic parameters of the reducer gears based on the set ratio relationship. The simulation module 202 is used to establish a dynamic model of the reducer system including the macroscopic parameters, apply wheel end impact load for simulation, and extract simulation result data related to the knocking noise; wherein, the simulation result data includes at least the peak value of angular acceleration, root mean square value of angular acceleration of the knocking section and impact torque of at least one shaft among the input shaft, intermediate shaft and differential. The data comparison module 203 is used to compare the simulation result data with the corresponding data of the initial impact vehicle model. If at least one of the peak angular acceleration, root mean square value of the impact segment angular acceleration, and impact torque does not achieve the preset optimization target compared to the initial impact vehicle model, the module returns to set the ratio relationship between the motor rotor inertia, input shaft inertia, intermediate shaft inertia, differential inertia, first-stage speed ratio, and second-stage speed ratio until the simulation result data meets the preset optimization target.

[0042] Regarding the apparatus in the above embodiments, the process of performing each step has been described in detail in the embodiments of the method, and will not be elaborated here.

[0043] Based on the same inventive concept, embodiments of this specification also provide an electronic device.

[0044] The following describes embodiments of the electronic device of the present invention, which can be considered as specific implementations of the methods and apparatus embodiments of the present invention described above. Details described in the embodiments of the electronic device of the present invention should be considered as supplements to the methods or apparatus embodiments described above; details not disclosed in the embodiments of the electronic device of the present invention can be implemented with reference to the methods or apparatus embodiments described above.

[0045] Reference Figure 3 This is a schematic diagram of an electronic device provided as an embodiment of this specification. Refer to the following... Figure 3 The electronic device 300 according to this embodiment of the present invention will be described. Figure 3 The electronic device 300 shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present invention.

[0046] like Figure 3 As shown, the electronic device 300 is presented in the form of a general-purpose computing device. The components of the electronic device 300 may include, but are not limited to: at least one processing unit 310, at least one storage unit 320, a bus 330 connecting different device components (including storage unit 320 and processing unit 310), a display unit 340, etc.

[0047] The storage unit stores program code that can be executed by the processing unit 310, causing the processing unit 310 to perform the steps described in the processing method section of this specification according to various exemplary embodiments of the present invention. For example, the processing unit 310 can perform, for example... Figure 1 The steps are shown.

[0048] The storage unit 320 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 3201 and / or a cache storage unit 3202, and may further include a read-only memory unit (ROM) 3203.

[0049] The storage unit 320 may also include a program / utility 3204 having a set (at least one) of program modules 3205, such program modules 3205 including but not limited to: operating devices, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0050] Bus 330 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0051] Electronic device 300 can also communicate with one or more external devices 400 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 300, and / or with any device that enables electronic device 300 to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 350. Furthermore, electronic device 300 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 360. Network adapter 360 can communicate with other modules of electronic device 300 via bus 330. It should be understood that, although... Figure 3 As not shown, other hardware and / or software modules may be used in conjunction with electronic device 300, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID devices, tape drives, and data backup storage devices.

[0052] Through the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described in this invention can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this invention can be embodied in the form of a software product, which can be stored in a computer-readable storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, or network device, etc.) to execute the method described above according to this invention. When the computer instructions are executed by a data processing device, the computer-readable medium is able to implement the method described above, i.e., as follows: Figure 1 The method shown.

[0053] Reference Figure 4 This is a schematic diagram of a computer-readable medium provided for embodiments of this specification.

[0054] accomplish Figure 1 The computer instructions of the method shown can be stored on one or more computer-readable media. A computer-readable medium can be a readable signal medium or a readable storage medium. A readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0055] The computer-readable storage medium may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium other than a readable storage medium, capable of transmitting, propagating, or transmitting a program for use by or in connection with an instruction execution device, apparatus, or apparatus. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0056] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0057] In summary, the present invention can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that in practice, general-purpose data processing devices such as microprocessors or digital signal processors (DSPs) can be used to implement some or all of the functions of some or all of the components according to the embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such programs implementing the present invention can be stored on a computer-readable medium or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0058] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the present invention is not inherently related to any specific computer, virtual device, or electronic device, and various general-purpose devices can also implement the present invention. The above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0059] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0060] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A design method for eliminating knocking noise from an electric vehicle reducer, characterized in that, including: setting the ratio relationship among the inertia of the motor rotor, the inertia of the input shaft, the inertia of the intermediate shaft, the inertia of the differential, the first-stage speed ratio and the second-stage speed ratio; and designing the macroscopic parameters of the reduction gear based on the set ratio relationship; establishing a dynamic model of the reduction gear system including the macroscopic parameters, applying a wheel-end impact load for simulation, and extracting simulation result data related to the knocking noise; wherein, the simulation result data at least includes the peak angular acceleration of at least one of the input shaft, the intermediate shaft and the differential, the root mean square value of the angular acceleration in the knocking section and the impact torque; comparing the simulation result data with the corresponding data of the initial knocking vehicle model, if at least one of the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section and the impact torque fails to achieve the preset optimization goal compared with the initial knocking vehicle model, then return to set the ratio relationship among the inertia of the motor rotor, the inertia of the input shaft, the inertia of the intermediate shaft, the inertia of the differential, the first-stage speed ratio and the second-stage speed ratio until the simulation result data meets the preset optimization goal.

2. The method according to claim 1, characterized in that, defining the total speed ratio i0 as the product of the first-stage speed ratio i1 and the second-stage speed ratio i2, and the ratio relationship includes speed ratio matching: when 8 < i0 < 13, i2 / i1 = 1.100 - 1.300; when 6 < i0 < 8, i2 / i1 = 1.200 - 1.

400.

3. The method according to claim 1 or 2, characterized in that, The ratio relationship includes inertia matching, and the inertia matching includes: the ratio J3 / J2 of the inertia J3 of the differential to the inertia J2 of the intermediate shaft is 5 - 11; the ratio J0 / J0 of the inertia J0 of the motor rotor to the inertia J0 of the input shaft is 55 - 110.

4. The design calculation method according to claim 1, characterized in that, The macroscopic parameters of the reduction gear include at least one of the number of teeth, module, pressure angle, helix angle, helix direction, tooth width and modification coefficient.

5. The design calculation method according to claim 1, characterized in that, The preset optimization goal is that at least one of the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section and the impact torque is at least 30% lower than that of the initial knocking vehicle model.

6. The design calculation method according to claim 6, characterized in that, The preset optimization goal further includes that at least one of the peak angular acceleration, the root mean square value of the angular acceleration in the knocking section and the impact torque is less than the corresponding data of the non-knocking vehicle model of the competing product for comparison.

7. The design calculation method according to claim 1, characterized in that, The wheel-end impact load is the wheel-end torque data under the actual rough road surface collected by a six-component force measuring instrument.

8. A design device for eliminating knocking noise from an electric vehicle speed reducer, characterized in that... , including: a parameter setting module for setting the ratio relationship among the inertia of the motor rotor, the inertia of the input shaft, the inertia of the intermediate shaft, the inertia of the differential, the first-stage speed ratio and the second-stage speed ratio; and designing the macroscopic parameters of the reduction gear based on the set ratio relationship; a simulation module for establishing a dynamic model of the reduction gear system including the macroscopic parameters, applying a wheel-end impact load for simulation, and extracting simulation result data related to the knocking noise; wherein, the simulation result data at least includes the peak angular acceleration of at least one of the input shaft, the intermediate shaft and the differential, the root mean square value of the angular acceleration in the knocking section and the impact torque; The data comparison module is used to compare the simulation result data with the corresponding data of the initial impact vehicle model. If at least one of the peak angular acceleration, root mean square value of the impact segment angular acceleration, and impact torque fails to achieve the preset optimization target compared to the initial impact vehicle model, the module returns to the setting of the ratio relationship between the motor rotor inertia, input shaft inertia, intermediate shaft inertia, differential inertia, first-stage speed ratio, and second-stage speed ratio until the simulation result data meets the preset optimization target.

9. An electronic device, characterized in that, The method includes a memory and a processor, wherein the memory stores computer instructions and the processor is configured to execute the computer instructions to perform the method according to any one of claims 1 to 7.

10. A storage medium, characterized in that, The storage medium stores computer instructions that are configured to execute the method described in any one of claims 1 to 7 when run.

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