A matching method of a whole vehicle driving semi-axle vibration absorber

Abstract

The application discloses a matching method of a whole vehicle driving half shaft vibration absorber, and is characterized in that the method comprises the following steps: step 1) analyzing the driving half shaft modal on a whole vehicle finite element model; step 2) selecting the vibration absorber based on the two-degree-of-freedom system damping principle; step 3) matching the vibration absorber based on the whole vehicle engine disturbance torque excitation passenger noise vibration response sensitivity; step 4) analyzing the vibration absorber frequency manufacturing error stability based on the whole vehicle WOT engine disturbance force / torque excitation passenger noise vibration response; and step 5) finally verifying the vibration absorber matching through a physical sample vehicle, and confirming the vibration absorber matching if the verification is qualified, or calibrating the whole vehicle simulation model, repeating the matching process based on the calibrated model until the verification is qualified or the result converges. The application is a forward development process of the driving half shaft vibration absorber, can match a short cycle, has high effect and low cost, and has strong practicability and good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of clearance measurement technology, and more specifically, relates to a matching method for a vehicle drive half-shaft vibration absorber. Background Technology

[0002] Front-engine, front-wheel-drive configurations are widely used in most sedans, especially small-displacement ones, due to their compact layout and spacious interior. The transmission output connects to the drive wheels via left and right drive half-shafts. Due to space constraints in the engine compartment, these half-shafts are often of unequal length. For frequency mitigation considerations related to the engine's main excitation frequency, the shorter shaft typically meets the requirements, while the longer shaft's modes often fall within the engine's main excitation frequency range. As a crucial transmission path, the drive half-shaft's resonance is transmitted to the vehicle body, resulting in noticeable vibration and noise for occupants. OEMs typically address this issue in two ways: 1. Designing the longer shaft as a three-section design significantly increases the modal frequency to meet mitigation requirements; 2. Adding vibration absorbers to the longer shaft to suppress its own vibration through resonance. Because three-section drive half-shafts are expensive, they are often used in mid-to-high-end sedans. Therefore, matching vibration absorbers to the long shaft of compact and small sedans is a crucial challenge for OEM NVH engineers.

[0003] The existing matching of drive half-shaft vibration absorbers is mainly carried out in the following ways: 1. Perform constrained modal analysis on the drive half-shaft using CAE to obtain modal frequencies and mode shapes. Determine the installation position of the vibration absorber based on the mode shapes (usually at the middle of the half-shaft). Determine the initial selection of vibration absorbers based on the frequencies (selecting multiple vibration absorbers within a deviation range of the analysis frequencies); 2. In the physical prototype stage, perform modal testing on the drive half-shaft on the entire vehicle. Based on the test results of the modal frequencies of the drive half-shaft on the actual vehicle, further screen the selected vibration absorbers (selecting several vibration absorbers within a deviation range of the test frequencies). Perform full-vehicle NVH testing on the screened vibration absorbers, and select the vibration absorber with the best test results as the final design. In actual development, step 1 can also be skipped, and matching can be performed directly in the physical prototype stage.

[0004] The main drawbacks of the above method are: 1. The CAE constrained modal analysis of the drive half-shaft results in discrepancies between the analysis results and the actual vehicle modes of the drive half-shaft; 2. The selection of the vibration absorber based on comparisons of several test results may not yield the optimal matching effect; 3. It is impossible to predict and avoid in advance the noise and vibration risks caused by the coupling effect of the resonance frequency on the vehicle body and chassis after adding the vibration absorber. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the prior art and provide a matching method for vehicle drive half-shaft vibration absorbers that has a short matching cycle, high efficiency and low cost.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows: The matching method for the vehicle drive half-shaft vibration absorber is characterized by the following steps: Step 1) Analyzing the drive half-shaft modes on the vehicle finite element model; Step 2) Selecting the vibration absorber based on the vibration reduction principle of a two-degree-of-freedom system; Step 3) Matching the vibration absorber based on the sensitivity of the vehicle engine disturbance torque excitation to the occupant noise vibration response; Step 4) Analyzing the stability of the vibration absorber frequency manufacturing error based on the vehicle WOT engine disturbance torque excitation to the occupant noise vibration response; Step 5) Finally, verifying the vibration absorber matching through a physical prototype vehicle. If the verification is successful, the vibration absorber matching is confirmed; if it is unsuccessful, the vehicle simulation model is calibrated, and the matching process is repeated based on the calibrated model until it is successful or the result converges.

[0007] To make the above technical solutions more detailed and specific, the present invention also provides the following further preferred technical solutions to achieve satisfactory practical effects:

[0008] In step 1), a finite element model of the whole vehicle is established and assembled according to the actual vehicle connection. The modal characteristics of the whole vehicle are calculated and the modal results of the drive half shaft are identified.

[0009] In step 2), the first-order mode of the drive half-shaft is regarded as the analysis result of a single-degree-of-freedom system. The vibration absorber structure is modeled in detail, and the material is assigned corresponding properties. The mode corresponding to the first-order mode frequency of the vibration absorber and the half-shaft is regarded as the analysis result of a single-degree-of-freedom system. The vibration absorber is installed on the drive half-shaft to form a two-degree-of-freedom system. Using the vibration reduction principle of the two-degree-of-freedom system and combined with engineering feasibility, the mass and frequency of the vibration absorber can be initially selected.

[0010] In step 3), a sinusoidal scanning unit torque is applied at the center of the crankshaft, and a sinusoidal scanning unit counter-torque is simultaneously applied at the corresponding position of the powertrain to calculate the vehicle noise and vibration response. The calculation model includes the state of the vehicle without vibration absorbers and the state of the vehicle with multiple vibration absorbers selected in step 2.

[0011] In step 3), the vibration reduction effect of the vibration absorber on the resonance peak of the original model and the influence of the two resonance frequencies formed after the vibration absorber is installed on the noise vibration response inside the vehicle are judged by comparing the results. If the vibration reduction and noise reduction effect is not ideal or the two resonance frequencies after the vibration absorber is installed form a new peak value for the noise vibration response inside the vehicle, on the one hand, the sample size of the vibration absorber selected in step 2) can be increased and the analysis can continue in step 3); on the other hand, the new peak value can be reduced or eliminated by optimizing the body or chassis structure.

[0012] In step 4), the WOT engine order excitation extracted from the powertrain mounting system multibody dynamics model and measured cylinder pressure is loaded onto the vehicle model to calculate the vehicle's WOT in-vehicle noise and vibration response; based on the technical requirements of vibration absorber frequency manufacturing deviation, the vibration absorber is assembled onto the vehicle model according to its design state, upper and lower deviation states, and an intermediate state is selected as appropriate to calculate the in-vehicle noise and vibration.

[0013] By comparing the results, the stability of the vibration response of the vehicle interior to the frequency manufacturing deviation of the vibration absorber is determined. If the stability is good, the vibration absorber design is confirmed. If the stability is poor, the second best result in step 3) is selected for analysis. This iterative process is repeated, and finally, the vibration reduction effect and stability are weighed and evaluated based on experience to confirm the vibration absorber design.

[0014] The vibration absorbers confirmed in step 4) are then tested in batches on vehicles. If they meet the development requirements, the matching development of the vibration absorbers is completed. If they do not meet the development requirements, the vehicle simulation model is calibrated by comparing the analysis results of the whole vehicle simulation model with the test results.

[0015] The calibrated simulation model is then subjected to analysis and calculations in steps 1 to 4 until the vibration absorber matching verification of the physical prototype vehicle meets the development requirements or a convergence result is obtained.

[0016] Compared with the prior art, the present invention has the following advantages: The matching method of the vehicle drive half-shaft vibration absorber of the present invention is a forward development process of drive half-shaft vibration absorber. This process is based on the finite element analysis of the whole vehicle and the vibration reduction principle of a two-degree-of-freedom system. In the engineering data design stage, the vibration absorber is optimized and matched, and the matching verification of the drive half-shaft vibration absorber is carried out on the tooling prototype vehicle. The goal of short cycle, high effect and low cost of drive half-shaft vibration absorber matching is achieved, which has strong practicality and good application prospects. Attached Figure Description

[0017] The following is a brief explanation of the contents depicted in the accompanying drawings and the markings therein:

[0018] Figure 1 This is a flowchart illustrating the matching process of the vehicle drive half-shaft vibration absorber of the present invention;

[0019] Figure 2 This is the result of the modal analysis of the vehicle drive half-shaft of this invention;

[0020] Figure 3 Modeling and assembly of the vibration absorber and half-shaft of this invention;

[0021] Figure 4 This invention illustrates the effect of the vibration absorber mass on the half-shaft vibration.

[0022] Figure 5 This invention illustrates the effect of the vibration absorber frequency on the half-shaft vibration.

[0023] Figure 6 The present invention relates to the sensitivity of the in-vehicle noise response to the excitation of engine disturbance torque. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and through the description of the examples.

[0025] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0026] This invention provides a matching method for a vehicle drive half-shaft vibration absorber. This method considers the influence of the vehicle assembly boundary on the drive half-shaft modes, analyzing the drive half-shaft modes on a finite element model of the vehicle; selecting the vibration absorber based on the vibration reduction principle of a two-degree-of-freedom system; matching the vibration absorber based on the sensitivity of the vehicle's engine disturbance torque excitation to occupant noise and vibration response; performing frequency manufacturing error stability analysis of the vibration absorber based on the vehicle's WOT engine disturbance / torque excitation to occupant noise and vibration response; and finally verifying the vibration absorber matching using a physical prototype vehicle. If the verification is successful, the vibration absorber matching is confirmed; if unsuccessful, the vehicle simulation model is calibrated, and the matching process is repeated based on the calibrated model until successful or the results converge. For the specific implementation process, see [link to implementation details]. Figure 1 The specific implementation method is as follows:

[0027] Drive axle modal analysis: A finite element model of the entire vehicle is established and assembled according to the actual vehicle connections. The modal characteristics of the entire vehicle are calculated, and the modal results of the drive axle are identified (the origin transfer function can be used to assist in identification). See the example results below. Figure 2 .

[0028] Vibration absorber selection based on the two-degree-of-freedom system vibration reduction principle: The first-order mode of the drive half-shaft is considered as the analysis result of a single-degree-of-freedom system. The vibration absorber structure (usually a cylindrical symmetrical steel + rubber structure) is modeled in detail, and corresponding material properties are assigned. The modes corresponding to the first-order modal frequencies of the vibration absorber and the half-shaft are considered as the analysis result of a single-degree-of-freedom system. The vibration absorber is installed on the drive half-shaft to form a two-degree-of-freedom system. See the example below. Figure 3 By applying the vibration reduction principle of a two-degree-of-freedom system and considering engineering feasibility, a preliminary selection of the vibration absorber's mass and frequency can be made. Examples of the influence of the absorber's mass and frequency on the half-shaft vibration are shown below. Figure 4 and Figure 5 .

[0029] Vibration absorber matching based on the sensitivity of the vehicle's engine disturbance torque to excitation of occupant noise and vibration response: From Figure 4 It can be seen that when the vibration absorber frequency is constant, the vibration absorber can play a damping role within a relatively large mass range. The two small peak frequencies tend to approach or move away as the mass of the vibration absorber changes. Whether there is a coupling effect with the overall vehicle structure or acoustic cavity needs to be analyzed through the overall vehicle noise and vibration response; from Figure 5 It is known that when the mass of the vibration absorber is constant, it can reduce vibration over a relatively large frequency range. The two smaller peak frequencies change in the same direction with the frequency of the vibration absorber. Whether there is a coupling effect with the overall vehicle structure or acoustic cavity needs to be analyzed through the overall vehicle noise and vibration response. This step involves applying a sinusoidal scanning unit torque at the crankshaft center position and simultaneously applying a sinusoidal scanning unit counter-torque at the corresponding position of the powertrain to calculate the overall vehicle noise and vibration response. The calculation model includes the vehicle without vibration absorbers and the vehicle with multiple vibration absorbers selected in step 2. The results are compared to determine: 1. The vibration reduction effect of the vibration absorber on the resonance peaks of the original model; 2. The magnitude of the influence of the two resonance frequencies formed after installing the vibration absorbers on the in-vehicle noise and vibration response. Example results of the noise response are shown below. Figure 6 By comparing and analyzing the results, if the vibration reduction and noise reduction effect is not ideal, or if the two resonant frequencies after installing the vibration absorber form new peaks in the vehicle's noise vibration response, on the one hand, the sample size of the selected vibration absorber can be increased in step 2, and the analysis can continue in step 3; on the other hand, the new peaks can be reduced or eliminated through optimization of the vehicle body or chassis structure. Using the above methods, the coupling effect of new resonant frequencies can be avoided while ensuring the vibration reduction and noise reduction effect of the vibration absorber.

[0030] Stability Analysis of Vibration Absorber Frequency Manufacturing Error Based on Vehicle-Wide Engine Disturbance / Torque Excitation of Occupant Noise and Vibration Response: Commonly used vibration absorbers are made of steel and rubber. Due to the complexity of the rubber manufacturing process, hardness deviations exist in the manufacturing results, thus the frequency of the vibration absorber will be within a deviation range. The vibration absorbers selected in step 3 are matched to the vehicle. The sensitivity of the vehicle's noise and vibration response to the vibration absorber frequency deviation should be minimized to ensure the feasibility of the actual vehicle solution. In this step, the WOT engine order excitation extracted from the powertrain mounting system multibody dynamics model and measured cylinder pressure is applied to the vehicle model to calculate the vehicle's WOT in-vehicle noise and vibration response. Based on the technical requirements for vibration absorber frequency manufacturing deviation, the vibration absorber is assembled onto the vehicle model according to its design state, upper and lower deviation states, and an intermediate state is selected as appropriate to calculate in-vehicle noise and vibration. By comparing the results, the stability of the in-vehicle noise and vibration response to the vibration absorber frequency manufacturing deviation is obtained. If the stability is good, the vibration absorber design is confirmed; if the stability is poor, the second-best option from step 3 is selected for analysis. This iterative process is repeated, and finally, the vibration reduction effect and stability are weighed and evaluated based on experience to confirm the vibration absorber design.

[0031] Physical prototype vibration absorber matching verification: The vibration absorbers confirmed in step 4 are batch-installed on vehicles for verification. If they meet the development requirements, the vibration absorber matching development is complete. If they do not meet the development requirements, the vehicle simulation model is calibrated by comparing the analysis results with the test results. The calibrated simulation model is then subjected to the analysis and calculations of steps 1 to 4 until the physical prototype vibration absorber matching verification meets the development requirements or a convergence result is obtained.

[0032] The above steps complete the matching of the vibration absorbers for the vehicle's drive half-shaft.

[0033] The matching method for the vibration absorber of the vehicle drive half shaft proposed in this invention has the following three main advantages:

[0034] This method is a system design approach that applies virtual simulation to the matching of drive half-shaft vibration absorbers, establishing a forward development process for drive half-shaft vibration absorbers. During the engineering data design phase, this method utilizes system analysis principles and methods (two-degree-of-freedom system vibration reduction principles, whole-vehicle finite element analysis methods) to optimize the matching of the drive half-shaft vibration absorbers. This ensures the vibration absorber's reduction effect on the original peak value of the drive half-shaft while mitigating coupling risks after matching the absorber. Simultaneously, it considers the impact of vibration absorber frequency manufacturing errors on vehicle noise and vibration, ensuring the effectiveness and stability of vibration reduction and noise reduction within the vehicle after the absorber is installed in the actual vehicle.

[0035] Finally, the method uses a prototype vehicle in the mass production data stage to verify the matching of the vibration absorber of the drive half shaft in the actual vehicle. If the development goal is not met, the model is calibrated by vehicle simulation, and the calibration model is analyzed again in steps 1-4 until the vibration absorber matching verification of the actual prototype vehicle meets the development requirements or a convergence result is obtained.

[0036] This invention patent proposes a matching method for a vehicle drive half-shaft vibration absorber. The key point is a forward development process for the drive half-shaft vibration absorber. This process is based on the finite element analysis of the whole vehicle and the vibration reduction principle of a two-degree-of-freedom system. In the engineering data design stage, the vibration absorber is optimized and matched, and the matching verification of the drive half-shaft vibration absorber is carried out on a tooling prototype vehicle. This achieves the goal of short-cycle, high-efficiency, and low-cost development of the drive half-shaft vibration absorber matching.

[0037] This invention provides a matching method for a vehicle drive half-shaft vibration absorber, and the protection point is a forward development process for a vehicle drive half-shaft vibration absorber. Any simple modifications (such as other simulation methods for vibration absorbers), equivalent changes, and modifications (such as matching vibration absorbers with other structures (such as sliding columns)) made to the above embodiments without departing from the scope of this invention are still within the protection scope of this invention.

[0038] The present invention has been described above by way of example with reference to the accompanying drawings. However, the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention or any direct application to other situations shall fall within the protection scope of the present invention.

Claims

1. A matching method for a vibration absorber of a vehicle drive half-shaft, characterized in that, The process includes the following steps: Step 1) Analyze the driving half-shaft modes on the finite element model of the whole vehicle; Step 2) Select a vibration absorber based on the vibration reduction principle of a two-degree-of-freedom system; Step 3) Match the vibration absorber based on the sensitivity of the vehicle's engine disturbance torque excitation to the occupant noise and vibration response; Step 4) Analyze the stability of the vibration absorber's frequency manufacturing error based on the vehicle's WOT engine disturbance torque excitation to the occupant noise and vibration response; Step 5) Finally, verify the vibration absorber matching using a physical prototype vehicle. If the verification is successful, the vibration absorber matching is confirmed. If it is unsuccessful, calibrate the whole vehicle simulation model and repeat the matching process based on the calibrated model until it is successful or the results converge. In step 3), a sinusoidal scanning unit torque is applied at the crankshaft center position, and a sinusoidal scanning unit counter-torque is simultaneously applied at the corresponding position of the powertrain to calculate the vehicle noise and vibration response. The calculation model includes the vehicle without vibration absorbers and the vehicle with multiple vibration absorbers selected in step 2. The results are compared to determine the vibration reduction effect of the vibration absorbers on the resonance peak of the original model and the influence of the two resonance frequencies formed after the vibration absorbers are installed on the vehicle's noise and vibration response. If the vibration reduction and noise reduction effect is not ideal or the two resonance frequencies after the vibration absorbers are installed form new peaks in the vehicle's noise and vibration response, on the one hand, the sample size of the vibration absorbers selected in step 2) can be increased, and the analysis can continue in step 3); on the other hand, the new peaks can be reduced or eliminated through body or chassis structure optimization.

2. The matching method for the vehicle drive half-shaft vibration absorber according to claim 1, characterized in that: In step 1), a finite element model of the whole vehicle is established and assembled according to the actual vehicle connection. The modal characteristics of the whole vehicle are calculated and the modal results of the drive half shaft are identified.

3. The matching method for the vehicle drive half-shaft vibration absorber according to claim 1, characterized in that: In step 2), the first-order mode of the driving half-shaft is regarded as the analysis result of a single-degree-of-freedom system. The vibration absorber structure is modeled in detail, and the material is assigned corresponding properties. The mode corresponding to the first-order mode frequency of the vibration absorber and the half-shaft is regarded as the analysis result of a single-degree-of-freedom system. The vibration absorber is installed on the drive half-shaft to form a two-degree-of-freedom system. By applying the vibration reduction principle of the two-degree-of-freedom system and combining it with engineering feasibility, the mass and frequency of the vibration absorber can be initially selected.

4. The matching method for the vehicle drive half-shaft vibration absorber according to claim 1, characterized in that: In step 4), the WOT engine order excitation extracted from the powertrain mounting system multibody dynamics model and measured cylinder pressure is loaded onto the vehicle model to calculate the vehicle's WOT in-vehicle noise and vibration response; based on the technical requirements of vibration absorber frequency manufacturing deviation, the vibration absorber is assembled onto the vehicle model according to its design state, upper and lower deviation states, and an intermediate state is selected as appropriate to calculate the in-vehicle noise and vibration.

5. The matching method for the vehicle drive half-shaft vibration absorber according to claim 4, characterized in that: By comparing the results, the stability of the vibration response of the vehicle interior to the frequency manufacturing deviation of the vibration absorber is determined. If the stability is good, the vibration absorber design is confirmed. If the stability is poor, the second best result in step 3) is selected for analysis. This iterative process is repeated, and finally, the vibration reduction effect and stability are weighed and evaluated based on experience to confirm the vibration absorber design.

6. The matching method for the vehicle drive half-shaft vibration absorber according to claim 1, characterized in that: The vibration absorbers confirmed in step 4) will be tested in batches on vehicles. If they meet the development requirements, the matching development of the vibration absorbers will be completed. If the development requirements are not met, the vehicle simulation model is calibrated by comparing the analysis results with the test results.

7. The matching method for the vehicle drive half-shaft vibration absorber according to claim 6, characterized in that: The calibrated simulation model is then subjected to analysis and calculations in steps 1) to 4) until the vibration absorber matching verification of the physical prototype vehicle meets the development requirements or a convergence result is obtained.

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