Nvh test method, device, equipment and medium for vehicle four-wheel drive transfer

Abstract

The application provides a vehicle four-wheel drive distributor NVH test method, device, equipment and medium. The vehicle four-wheel drive distributor is arranged on a test bench. The test bench comprises a load dynamometer and a drive dynamometer. The method comprises the following steps: arranging vibration acceleration sensors and sound sensors at preset positions of the vehicle four-wheel drive distributor, wherein the preset positions comprise positions on the vehicle four-wheel drive distributor and positions around the vehicle four-wheel drive distributor; obtaining a preset test strategy of the vehicle four-wheel drive distributor; controlling the load dynamometer and the drive dynamometer according to the preset test strategy, so as to obtain vibration information and sound information of the vehicle four-wheel drive distributor through the vibration acceleration sensors and the sound sensors; and generating an NVH test result of the vehicle four-wheel drive distributor according to the preset test strategy, the vibration information and the sound information. Therefore, the NVH result of the four-wheel drive distributor can be accurately tested, and data support for improving the comfort of the whole vehicle is provided.

Description

Technical Field

[0001] This application relates to the field of NVH testing technology, and in particular to an NVH testing method, apparatus, equipment and medium for a vehicle four-wheel drive transfer case. Background Technology

[0002] As a key component for power transmission and distribution, the NVH (Noise, Vibration, and Harshness) performance of the four-wheel drive transfer case is particularly crucial. During vehicle operation, the meshing of gears, the operation of bearings, and the engagement and slippage of the multi-plate clutches within the transfer case all generate vibration and noise. These vibrations are transmitted to the vehicle interior through the subframe and body structure, while the resulting airborne noise also directly radiates into the cabin, collectively affecting the comfort of the occupants. However, traditional NVH testing methods for automotive components mostly focus on single components such as the engine, transmission, and drive axle. The test conditions, measurement point arrangements, and equipment parameters of these methods are designed for the specific structural and operational characteristics of these components, making it difficult to adapt to the transmission logic and complex operating conditions of four-wheel drive transfer cases. Therefore, the industry urgently needs a bench testing method for the NVH of four-wheel drive transfer cases. Summary of the Invention

[0003] This application aims to at least partially address one of the technical problems in the related art.

[0004] Therefore, the first objective of this application is to propose an NVH testing method for a vehicle four-wheel drive transfer case, which can accurately collect vibration and sound data of the four-wheel drive transfer case through bench testing, and generate NVH results by combining testing strategies, thereby providing data support for improving the overall vehicle comfort.

[0005] The second objective of this application is to provide an NVH testing device for a vehicle four-wheel drive transfer case.

[0006] The third objective of this application is to propose an electronic device.

[0007] The fourth objective of this application is to provide a computer-readable storage medium.

[0008] To achieve the above objectives, the first aspect of this application proposes an NVH testing method for a vehicle four-wheel drive transfer case, comprising the following steps: arranging a vibration acceleration sensor and a sound sensor at preset positions on the vehicle four-wheel drive transfer case, wherein the preset positions include positions on the vehicle four-wheel drive transfer case and positions around the vehicle four-wheel drive transfer case; acquiring a preset testing strategy for the vehicle four-wheel drive transfer case; controlling a load dynamometer and a drive dynamometer according to the preset testing strategy to acquire vibration information and sound information of the vehicle four-wheel drive transfer case through the vibration acceleration sensor and the sound sensor, respectively; and generating NVH test results for the vehicle four-wheel drive transfer case based on the preset testing strategy, the vibration information, and the sound information.

[0009] The NVH testing method for a vehicle four-wheel drive transfer case according to an embodiment of this application firstly arranges vibration acceleration sensors and sound sensors at preset locations on the vehicle four-wheel drive transfer case, including positions on the transfer case itself and positions around the transfer case. Then, a preset testing strategy for the vehicle four-wheel drive transfer case is acquired. Next, a load dynamometer and a drive dynamometer are controlled according to the preset testing strategy to acquire vibration and sound information of the vehicle four-wheel drive transfer case through the vibration acceleration sensors and sound sensors, respectively. Finally, based on the preset testing strategy, vibration information, and sound information, the NVH test results of the vehicle four-wheel drive transfer case are generated. Therefore, it is possible to accurately collect vibration and sound data of the four-wheel drive transfer case through bench testing, and generate NVH results by combining the test strategy, providing data support for improving overall vehicle comfort.

[0010] In addition, the NVH testing method for the vehicle four-wheel drive transfer case according to the above embodiments of this application may also have the following additional technical features:

[0011] In one embodiment of this application, the test bench further includes a drive axle input drive shaft, a drive axle output drive shaft, a test drive axle, and a subframe. The vehicle's four-wheel drive transfer case is mounted on the drive dynamometer via a connecting plate. The input end of the vehicle's four-wheel drive transfer case is connected to the main shaft of the drive dynamometer. The first output end of the vehicle's four-wheel drive transfer case is connected to the input end of the test drive axle via the drive axle input drive shaft. The output end of the test drive axle is connected to the load dynamometer via the drive axle output drive shaft. The test drive axle is mounted on the subframe.

[0012] In one embodiment of this application, the output end of the test drive bridge includes a first output end and a second output end, the load dynamometer includes a first load dynamometer and a second load dynamometer, and the drive bridge output transmission shaft includes a first drive bridge output transmission shaft and a second drive bridge output transmission shaft. The first output end of the test drive bridge is connected to the first load dynamometer through the first drive bridge output transmission shaft, and the second output end of the test drive bridge is connected to the second load dynamometer through the second drive bridge output transmission shaft.

[0013] In one embodiment of this application, the test bench further includes an anechoic chamber, in which the vehicle four-wheel drive transfer case, drive dynamometer, drive axle input drive shaft, drive axle output drive shaft, auxiliary drive axle and subframe are all disposed. The load dynamometer is disposed outside the anechoic chamber and is connected to the drive axle output drive shaft via a through-wall shaft and intermediate support.

[0014] In one embodiment of this application, the vibration acceleration sensor includes a first vibration acceleration sensor and a second vibration acceleration sensor, and there are multiple sound sensors. The first vibration acceleration sensor is disposed at the input end of the vehicle's four-wheel drive transfer case, and the second vibration acceleration sensor is disposed at the connecting plate. The multiple sound sensors are respectively disposed around the vehicle's four-wheel drive transfer case, wherein the vertical distance between the sound sensors and the housing of the vehicle's four-wheel drive transfer case is a first preset distance.

[0015] In one embodiment of this application, a preset test strategy, vibration information, and sound information are used to generate NVH test results for a vehicle four-wheel drive transfer case. This includes: parsing the preset test strategy to obtain state information of the vehicle four-wheel drive transfer case; analyzing the vibration information based on a first preset analysis frequency to obtain target vibration data; analyzing the sound information based on a second preset analysis frequency to obtain target sound data, wherein the second preset analysis frequency is greater than the first preset analysis frequency; and generating NVH test results for the vehicle four-wheel drive transfer case based on the state information, target vibration data, and target sound data, wherein the NVH test results include a sound vibration spectrum.

[0016] In one embodiment of this application, the status information includes one or more of the following for the vehicle's four-wheel drive transfer case: load input, load output, operating condition, input speed, output speed, input torque, clutch clamping force, and slip torque.

[0017] To achieve the above objectives, a second aspect of this application provides an NVH testing device for a vehicle four-wheel drive transfer case, comprising: an arrangement module for arranging a vibration acceleration sensor and a sound sensor at preset positions on the vehicle four-wheel drive transfer case, wherein the preset positions include positions on the vehicle four-wheel drive transfer case and positions around the vehicle four-wheel drive transfer case; an acquisition module for acquiring a preset testing strategy for the vehicle four-wheel drive transfer case; a control module for controlling a load dynamometer and a drive dynamometer according to the preset testing strategy, so as to acquire vibration information and sound information of the vehicle four-wheel drive transfer case through the vibration acceleration sensor and the sound sensor, respectively; and a generation module for generating NVH test results of the vehicle four-wheel drive transfer case based on the preset testing strategy, vibration information, and sound information.

[0018] The NVH testing device for a vehicle four-wheel drive transfer case according to an embodiment of this application first arranges vibration acceleration sensors and sound sensors at preset positions on the vehicle four-wheel drive transfer case using an arrangement module. These preset positions include those on the transfer case itself and those surrounding it. Then, an acquisition module acquires a preset testing strategy for the four-wheel drive transfer case. Next, a control module controls a load dynamometer and a drive dynamometer according to the preset testing strategy to acquire vibration and sound information from the four-wheel drive transfer case via the vibration acceleration sensors and sound sensors, respectively. Finally, a generation module generates the NVH test results for the four-wheel drive transfer case based on the preset testing strategy, vibration information, and sound information. Therefore, it can accurately collect vibration and sound data of the four-wheel drive transfer case through bench testing, and generate NVH results by combining them with the testing strategy, providing data support for improving overall vehicle comfort.

[0019] To achieve the above objectives, a third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the NVH testing method for a vehicle four-wheel drive transfer case as described above.

[0020] The electronic device according to the embodiments of this application implements any of the above-mentioned NVH testing methods for vehicle four-wheel drive transfer cases when the processor executes a computer program. It realizes the accurate acquisition of vibration and sound data of the four-wheel drive transfer case through bench testing, and generates NVH results in combination with the testing strategy, providing data support for improving the overall vehicle comfort.

[0021] To achieve the above objectives, a fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement any of the above-described NVH test methods for a vehicle four-wheel drive transfer case.

[0022] According to the embodiments of this application, a computer-readable storage medium storing a computer program thereon implements any of the above-mentioned NVH testing methods for a vehicle four-wheel drive transfer case when executed by a processor. This method enables the accurate acquisition of vibration and sound data of the four-wheel drive transfer case through bench testing, and generates NVH results by combining the test strategy, thus providing data support for improving the overall vehicle comfort.

[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0024] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1This is a schematic flowchart of an NVH testing method for a vehicle four-wheel drive transfer case according to some embodiments of this application; Figure 2 This is a schematic diagram of the test bench installation for a vehicle four-wheel drive transfer case according to some embodiments of this application; Figure 3 This is a schematic diagram of the installation of a sound sensor and a vibration acceleration sensor according to some embodiments of this application; Figure 4 This is a flowchart illustrating an NVH testing method for a vehicle four-wheel drive transfer case according to a specific embodiment of this application. Figure 5 This is a diagram showing the vibration test results of a vehicle four-wheel drive transfer case according to a specific embodiment of this application; Figure 6 A block diagram of an NVH testing apparatus for a vehicle four-wheel drive transfer case according to some embodiments of this application; and Figure 7 This is a schematic diagram of the structure of an electronic device according to some embodiments of this application. Detailed Implementation

[0025] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0026] The NVH testing method, apparatus, equipment, and medium for a vehicle four-wheel drive transfer case according to embodiments of this application are described below with reference to the accompanying drawings.

[0027] It should be noted that, in the embodiments of this application, as... Figure 2As shown, the vehicle's four-wheel drive transfer case 6 is mounted on a test bench, which may include a load dynamometer 1 and a drive dynamometer 7. Specifically, during vehicle operation, various interference sources such as engine noise and road surface excitation will superimpose with the NVH signal of the transfer case 6, resulting in extremely low reliability of the test results. By mounting the transfer case 6 on a dedicated test bench, the test environment can be confined to a controlled laboratory space, reducing external interference. Simultaneously, the bench provides a stable mounting base, avoiding additional vibrations caused by changes in vehicle body posture and uneven road surfaces during actual vehicle operation, ensuring the stability and repeatability of the test process. The drive dynamometer 7 replaces the engine and transmission in the vehicle, and can precisely apply the required speed and drive torque, or apply anti-drag torque, to the input end of the four-wheel drive transfer case 6 according to a preset program, enabling the reproduction of dynamic driving conditions in a laboratory environment. The load dynamometer 1 is connected to the output end of the four-wheel drive transfer case 6, used to absorb its output power and precisely apply controllable load torque to simulate the ground resistance experienced by the wheels under different road conditions and driving states. Integrating the drive dynamometer 7 and the load dynamometer 1 into a controllable test bench system can accurately and repeatably simulate the complex dynamic working conditions experienced by the vehicle's four-wheel drive transfer case 6 on a real vehicle, which is the core prerequisite for the implementation of subsequent methods.

[0028] The NVH testing method for the vehicle four-wheel drive transfer case provided in this application embodiment can be performed by an electronic device, such as a mobile phone, tablet computer, handheld computer, or server, etc., without any limitation.

[0029] In this embodiment, the electronic device may include a processing component, a storage component, and a driving component. Optionally, the driving component and the processing component may be integrated, and the storage component may store an operating system, application programs, or other program modules. The processing component implements the NVH testing method for the vehicle four-wheel drive transfer case provided in this embodiment by executing the application programs stored in the storage component.

[0030] like Figure 1 As shown, the NVH testing method for a vehicle four-wheel drive transfer case according to an embodiment of this application may include the following steps: Step S1: A vibration acceleration sensor and a sound sensor are respectively placed at preset positions on the vehicle's four-wheel drive transfer case. The preset positions include those on the four-wheel drive transfer case itself and those around it. The preset positions can be calibrated according to actual conditions.

[0031] Specifically, the vibration acceleration sensor is used to directly collect vibration signals generated by the operation of the four-wheel drive transfer case itself. Its placement must be close to the transfer case body to ensure that the vibration signal can be directly transmitted to the sensor. Therefore, the preset position should be selected on the surface of the transfer case housing, preferably in an area where the vibration excitation source is concentrated and the vibration transmission path is critical. The sound sensor is used to collect airborne sound signals radiated into the surrounding environment during the operation of the four-wheel drive transfer case. Its placement must balance the integrity of signal acquisition and anti-interference capabilities. Therefore, the preset position is set around the key acoustic radiation area around the transfer case. During calibration, the operability of sensor installation must be considered, avoiding selecting preset positions in areas with limited space, where it is impossible to fix the sensor, or where directional calibration is impossible, ensuring that the placement operation can be completed smoothly.

[0032] The selection of preset locations must be combined with the operating conditions in the subsequent preset test strategy to ensure that the preset locations can stably collect signals under various operating conditions, and that signal acquisition will not be interrupted or distorted due to the switching of transfer case operating conditions. During installation, if the signal collected at a certain placement point has obvious attenuation, excessive noise, or cannot reflect the vibration / noise characteristics of the core operating state of the transfer case, the location must be adjusted, and a new placement point with clear and stable signals must be selected to ensure that vibration and noise data can be collected in real time and accurately during subsequent testing.

[0033] Step S2: Obtain the preset test strategy for the vehicle's four-wheel drive transfer case. The preset test strategy can be calibrated according to actual conditions.

[0034] Specifically, the preset test strategy is a pre-defined test plan framework for evaluating the NVH performance of a vehicle's four-wheel drive transfer case. Its core function is to provide a clear execution basis for subsequent control of the dynamometer and collection of vibration and sound information, ensuring that the test process is orderly and efficient, and that the test results can truly reflect the NVH performance of the transfer case in actual use scenarios.

[0035] In this embodiment, the preset test strategy includes, but is not limited to, the operating condition dimension, the dynamic process dimension, and the load and control system dimension. Firstly, the operating condition dimension defines the basic operating modes, which may include rear-wheel drive mode and four-wheel drive mode. The rear-wheel drive mode simulates the state where the internal clutch of the transfer case is disengaged and power is only output to the rear axle, which is used to evaluate its basic NVH characteristics as a drive shaft. The four-wheel drive mode simulates the state where the clutch is engaged and power is distributed between the front and rear axles. It can be further subdivided into no-speed-difference operating conditions and speed-difference operating conditions. The no-speed-difference operating condition simulates the vehicle driving in a straight line with the front and rear axle speeds synchronized, which is used to evaluate the load-bearing NVH performance of the gear system and bearings when torque is distributed. The speed-difference operating condition simulates situations such as the vehicle turning, where there is a preset speed difference between the front and rear axles, forcing the multi-plate clutch into a controllable slip friction state, which is used to stimulate and evaluate unique NVH problems such as clutch friction noise and chatter. Secondly, the dynamic process dimension defines the time-state change process under each mode, which can include the forward-drive uniform acceleration process, the reverse-drag uniform deceleration process, and the steady-state operating point. The forward-drive uniform acceleration process simulates the vehicle's acceleration from low speed to high speed, with the drive dynamometer providing the forward drive torque. The reverse-drag uniform deceleration process simulates the vehicle's coasting in gear or engine braking, with the drive dynamometer providing the reverse torque to examine the meshing noise and vibration characteristics of the gear teeth on the opposite side. The steady-state operating point maintains stable operation at a specific speed and torque, used for detailed spectrum analysis and problem localization. Thirdly, the load and control system dimension defines the precise control parameters required to achieve the above operating conditions, which can include input conditions, output conditions, and clutch control. The input conditions are the input speed and input torque controlled by the drive dynamometer. The output conditions are the load torque (i.e., simulated driving resistance) applied by the load dynamometer. For electronically controlled multi-plate clutch transfer cases, the strategy must include instructions for clutch clamping force or target slip torque to precisely control its engagement state and slip.

[0036] The calibration of the preset test strategy should be combined with the basic technical parameters of the four-wheel drive transfer case to be tested and the NVH test objectives. After the strategy is formulated, its feasibility and completeness should be verified to confirm that all working condition settings and parameter requirements meet the actual test needs. After confirming the feasibility of the strategy, it can be stored in the system so that it can be directly called in subsequent tests to improve test efficiency.

[0037] Step S3: Control the load dynamometer and drive dynamometer according to the preset test strategy to obtain the vibration information and sound information of the vehicle's four-wheel drive transfer case through the vibration acceleration sensor and sound sensor, respectively.

[0038] Specifically, the load dynamometer applies corresponding resistance torque to the transfer case output based on the output load requirements in the preset strategy, simulating road resistance during actual vehicle operation. For example, in rear-wheel drive mode, a load is applied to the load dynamometer at the corresponding rear-wheel drive output, while the load dynamometer at the front output is unloaded. In four-wheel drive mode with no speed difference, the load dynamometers at both the front and rear outputs apply balanced load torque to ensure synchronized front and rear axle speeds. In four-wheel drive mode with a speed difference, the load difference between the two load dynamometers is adjusted to create a preset speed difference between the front and rear axles, simulating a vehicle turning scenario. Simultaneously, the load dynamometer needs to provide real-time feedback of the actual load value, coordinating with the power input of the drive dynamometer to ensure the transfer case's workload remains stable within the preset range, providing a stable operating condition basis for subsequent accurate data analysis.

[0039] The drive dynamometer precisely outputs corresponding power to the transfer case input based on the input speed and torque parameters in the preset strategy. For example, under forward drive uniform acceleration, the drive dynamometer is controlled to uniformly increase its speed according to a preset speed gradient (e.g., 500-3000 r / min) and increase rate, while simultaneously outputting the corresponding forward drive torque to ensure that the power input to the transfer case is consistent with the actual vehicle acceleration scenario. Under reverse drag uniform deceleration, the drive dynamometer is controlled to output reverse torque, driving the transfer case to uniformly decrease from a high speed (e.g., 3000 r / min) to a low speed (e.g., 500 r / min), simulating the reverse drag state during actual vehicle coasting deceleration. Throughout the entire control process, the speed and torque output values ​​of the drive dynamometer are monitored in real time. If parameter deviations occur (e.g., exceeding the preset fluctuation range), the control system immediately issues adjustment commands to ensure stable power input. It is important to note that the control of the drive dynamometer and the load dynamometer should be highly synchronized to ensure that the recorded vibration and sound data are aligned with the operating parameters such as speed and torque at each moment on the time axis. This is a prerequisite for subsequent order analysis, spectrum analysis and operating condition correlation.

[0040] While the dynamometer accurately reproduces the preset operating conditions, the vibration acceleration sensor and sound sensor are activated to synchronously collect the vibration and sound information of the transfer case. Key operating conditions should be repeatedly measured to verify data repeatability and eliminate random errors. In this embodiment, the sound level meter (including the sound sensor) used should meet the requirements of Class I sound level meters as specified in GB / T 3785.1. Before and after each measurement sequence, each sound level meter should be calibrated using a Class I sound calibrator conforming to GB / T 15173. Without any adjustments, the deviation between the readings of two calibrations should not exceed 0.5 dB. If this deviation exceeds the tolerance, the sound data obtained during that measurement is considered invalid, and the test must be re-tested after investigating equipment or environmental causes.

[0041] For the data acquisition and analysis system, vibration acceleration signals along each axis must be acquired synchronously at a sufficiently high sampling rate (usually no less than twice the preset highest analysis frequency). The A / D conversion resolution of the acquisition system itself should be no less than 24 bits to provide a high dynamic range and ensure that both weak and strong signals are recorded without distortion. Simultaneously, the data acquisition and analysis system should also integrate synchronous measurement and real-time spectrum analysis functions for parameters such as sound pressure level, vibration level, rotational speed, and torque. This not only enables online monitoring of data quality and preliminary diagnosis of operating conditions during testing, but also ensures the standardization and integrity of the acquired raw data in terms of format, timing, and parameter dimensions. This provides a standardized, high-quality raw dataset for subsequent data preprocessing, multi-dimensional signal analysis, and the generation of final NVH test results.

[0042] Step S4: Generate NVH test results for the vehicle's four-wheel drive transfer case based on the preset test strategy, vibration information, and sound information.

[0043] Specifically, firstly, the preset test strategy is analyzed to extract state information reflecting the transfer case's operating status throughout the test. Simultaneously, the collected vibration acceleration and sound signals undergo preprocessing operations such as filtering, noise reduction, and outlier removal. Then, based on the operating condition sequence and parameter information in the preset test strategy, the preprocessed vibration and sound information are correlated with the corresponding operating conditions. Next, based on the correlated data, signal processing is performed according to predetermined analysis parameters. In this embodiment, vibration acceleration signal analysis requires setting technical parameters suitable for structural vibration analysis. For example, based on the characteristics of the vibration signal and the frequency band of interest, an appropriate upper limit for the analysis frequency is set, and based on this, filtering, spectrum transformation, and other operations are performed to extract target vibration data reflecting the structural vibration characteristics of the transfer case, such as the vibration acceleration level spectrum and the change of the effective value of vibration velocity with operating conditions. Sound signal analysis typically uses a higher upper limit for the analysis frequency. Through analysis, target sound data reflecting the noise radiation characteristics of the transfer case are extracted, such as the A-weighted sound pressure level spectrum, the total sound pressure level change curve with operating conditions, and prominent discrete noise components. Finally, by combining the status information, target vibration data, and target sound data, the final NVH test results are generated. These results can be presented in graphical form, such as an overall trend chart or a detailed spectrum diagram. By summarizing the test data at each operating point and comparing them with preset targets or benchmarks, a clear performance evaluation conclusion is formed. The data can also be archived and stored for easy comparison processing later.

[0044] This embodiment first places vibration acceleration sensors and sound sensors at predetermined locations on and around the vehicle's four-wheel drive transfer case. Then, a predetermined test strategy for the four-wheel drive transfer case is acquired. Next, a load dynamometer and a drive dynamometer are controlled according to the predetermined test strategy to acquire vibration and sound information from the four-wheel drive transfer case via the vibration acceleration sensors and sound sensors, respectively. Finally, based on the predetermined test strategy, vibration information, and sound information, NVH test results for the four-wheel drive transfer case are generated. Therefore, it is possible to accurately collect vibration and sound data of the four-wheel drive transfer case through bench testing, and generate NVH results by combining the test strategy, providing data support for improving overall vehicle comfort.

[0045] In some embodiments of this application, such as Figure 2 As shown, the test bench may also include a drive axle input drive shaft 8, a drive axle output drive shaft 3, a test drive axle 5, and a subframe 4. The vehicle four-wheel drive transfer case 6 is mounted on the drive dynamometer 7 via a connecting plate. The input end of the vehicle four-wheel drive transfer case 6 is connected to the main shaft of the drive dynamometer 7. The first output end of the vehicle four-wheel drive transfer case 6 is connected to the input end of the test drive axle 5 via the drive axle input drive shaft 8. The output end of the test drive axle 5 is connected to the load dynamometer 1 via the drive axle output drive shaft 3. The test drive axle 5 is mounted on the subframe 4.

[0046] Specifically, the test drive axle 5 is an assembly on a test bench used to simulate the function of a real vehicle drive axle. Internally, it typically contains a main reducer (for speed reduction and torque increase) and a differential (allowing for speed differences between the left and right output ends), and is a key transmission component connecting the output of the transfer case 6 to the wheels (simulated by the load dynamometer 1 on the test bench). The drive axle input drive shaft 8 is a drive shaft connecting the output end of the four-wheel drive transfer case 6 and the input end of the test drive axle 5, used to transmit power. The drive axle output drive shaft 3 is a drive shaft connecting the output end of the test drive axle 5 and the load dynamometer 1, used to transmit power to the load and withstand simulated driving resistance. The subframe 4 is a rigid frame structure on the test bench used to mount and support the test drive axle 5, simulating the installation state and boundary conditions of the drive axle on the vehicle. The connecting plate refers to a special flange for achieving a high-rigidity, high-coaxiality connection between the main shaft of the drive dynamometer 7 and the input end of the four-wheel drive transfer case 6.

[0047] The four-wheel drive transfer case 6 does not directly drive the wheels in the vehicle; its output transmits power to the wheels via the drive axle. The drive axle itself is a rotating assembly containing gear pairs, with specific transmission ratios, inertia, and meshing characteristics. In bench testing, directly connecting the load dynamometer to a simple drive shaft would negate the impact of missing this crucial drive axle component.

[0048] Specifically, the test drive axle 5 incorporates the same reduction ratio and moment of inertia as the actual vehicle. This ensures that the rotational speed and dynamic load on the output shaft of the transfer case 6 are consistent with those of the actual vehicle, resulting in a more realistic gear meshing state and bearing load. The meshing of the drive axle's main reduction gear itself generates vibration and noise, which is transmitted in reverse through the drive shaft to the transfer case 6, forming mutually coupled excitations. Using the test drive axle 5, this dynamic coupling effect between multi-stage transmission systems can be reproduced, allowing the NVH data measured on the test bench to better reflect its true performance in the vehicle. The test drive axle 5 is mounted on the subframe 4, simulating its suspension state on the vehicle's subframe 4. This better reflects the path characteristics of vibration transmission through the suspension than rigid support.

[0049] In this embodiment, the drive dynamometer 7 serves as the power source. Its main shaft is connected to the input end of the four-wheel drive transfer case 6 via a connecting plate. The first output end of the transfer case 6 (usually the front output shaft) is connected to the input end of the test drive axle 5 via the drive axle input transmission shaft 8. The output end of the test drive axle 5 is connected to the corresponding load dynamometer 1 via the drive axle output transmission shaft 3. In this way, the resistance torque applied by the load dynamometer 1, after being decelerated and amplified by the test drive axle 5, can act on the output end of the transfer case 6 in a more realistic load form. The test drive axle 5 is mounted directly or via elastic elements on the subframe 4, which is then fixed to the foundation or experimental platform. This subframe 4 simulates the local stiffness of the entire vehicle structure, and its dynamic characteristics affect the resonance frequency of the entire test system. Thus, a test bench structure that more closely resembles the power transmission path of a real vehicle can be constructed.

[0050] In some embodiments of this application, such as Figure 2 As shown, the output terminals of the test drive bridge 5 may include a first output terminal and a second output terminal of the test drive bridge 5, the load dynamometer may include a first load dynamometer and a second load dynamometer, and the drive bridge output transmission shaft may include a first drive bridge output transmission shaft and a second drive bridge output transmission shaft. The first output terminal of the test drive bridge 5 is connected to the first load dynamometer through the first drive bridge output transmission shaft, and the second output terminal of the test drive bridge 5 is connected to the second load dynamometer through the second drive bridge output transmission shaft.

[0051] Specifically, by setting up two independent load dynamometers 1, which are respectively connected to the left and right output ends 3 of the test drive axle 5, a test bench structure that is closer to the power transmission path of the actual vehicle can be constructed, making the force distribution and power distribution characteristics of the transfer case 6 closer to those of the actual vehicle.

[0052] In this embodiment, the first output end of the test drive axle 5 is connected to the main shaft of the first load dynamometer located outside the anechoic chamber 2 via the first drive axle output drive shaft, passing through the corresponding acoustic partition or support. The second output end of the test drive axle 5 is connected to the second load dynamometer in a similar manner via the second drive axle output drive shaft. During the test, the drive dynamometer 7 provides power to the input end of the transfer case 6, which is then distributed by the transfer case 6 and transmitted to the test drive axle 5. The test drive axle 5 then distributes the power to the dual output ends 3, ultimately transmitting it to the dual load dynamometer 1. The dual load dynamometer 1 can apply resistance torque synchronously or independently according to a preset test strategy, thereby accurately simulating different working conditions.

[0053] For example, equal or proportionally distributed load torques can be applied to the first and second load dynamometers to accurately simulate the balanced ground resistance experienced by the left and right wheels of the vehicle. This ensures that the differential gears inside the transfer case 6 and the drive axle are in a straight-line engagement state without differential slippage, thereby evaluating its NVH level under this basic operating condition. As another example, different load torques can be applied to the two load dynamometers (e.g., applying less resistance to the load dynamometer simulating the outer wheel and more resistance to the load dynamometer simulating the inner wheel), causing the differential inside the test drive axle 5 to actuate. This creates a controllable speed difference between the first output end of the transfer case 6 and the two load dynamometers. This speed difference is further transmitted to the multi-plate clutch inside the four-wheel drive transfer case 6, causing it to enter a preset slipping state, thereby stimulating and evaluating transfer case-specific NVH problems such as "clutch slippage noise" and "differential gear knocking."

[0054] In some embodiments of this application, such as Figure 2 As shown, the test bench may also include an anechoic chamber 2, a vehicle four-wheel drive transfer case 6, a drive dynamometer 7, a drive axle input drive shaft 8, a drive axle output drive shaft 3, a test drive axle 5, and a subframe 4, all of which are located inside the anechoic chamber 2. The load dynamometer 1 is located outside the anechoic chamber 2 and is connected to the drive axle output drive shaft 3 via a through-wall shaft and an intermediate support.

[0055] Specifically, considering that the drive dynamometer 7 and auxiliary equipment such as the load dynamometer generate significant noise during operation, if they share the same unprocessed space with the test component, their noise will severely interfere with the transfer case's NVH test signal. Therefore, if... Figure 2 As shown, in this embodiment, the vehicle's four-wheel drive transfer case 6 and its directly connected mechanical parts (such as the drive dynamometer 7, the test drive axle 5, the subframe 4, and the drive shaft connecting them) are placed inside the anechoic chamber 2. The inner wall of the anechoic chamber 2 can be lined with professional sound-absorbing materials such as glass wool and polyester fiber sound-absorbing panels, which can effectively absorb indoor sound waves, significantly reduce the influence of reflected sound and environmental noise, and create a near-reflection-free free sound field inside the chamber, providing a pure acoustic environment for accurate noise testing.

[0056] Meanwhile, the load dynamometer 1 is separately arranged outside the anechoic chamber 2, and its power connection to the drive axle output transmission shaft 3 inside the chamber is achieved through a through-wall shaft and intermediate support. This ensures the continuity of power transmission, allowing the through-wall shaft to accurately transmit torque. The intermediate support provides stable support for the shaft system and reduces rotational vibration. Furthermore, the walls of the anechoic chamber 2 isolate the noise of the load dynamometer 1 from the core testing area, preventing interference with the noise testing of the transfer case 6. A special sound-insulating sealing kit is installed at the point where the through-wall shaft passes through the walls of the anechoic chamber 2, effectively blocking airborne sound leakage and ensuring the acoustic sealing performance of the anechoic chamber 2. The intermediate support adopts a low-vibration-transmission structural design and undergoes targeted vibration isolation treatment to minimize the transmission of structural vibrations into the anechoic chamber 2 through the bearing housing and walls, avoiding additional vibration interference and further ensuring the authenticity of the test data.

[0057] In some embodiments of this application, such as Figure 3 As shown, the vibration acceleration sensor 2 includes a first vibration acceleration sensor and a second vibration acceleration sensor, and multiple sound sensors 1 are present. The first vibration acceleration sensor is located at the input end of the vehicle's four-wheel drive transfer case, and the second vibration acceleration sensor is located at the connecting plate. The multiple sound sensors 1 are respectively located around the vehicle's four-wheel drive transfer case, and the vertical distance between the sound sensor 1 and the housing of the vehicle's four-wheel drive transfer case is a first preset distance. The first preset distance can be calibrated according to actual conditions.

[0058] Specifically, in this embodiment, the first vibration acceleration sensor is arranged on the surface of the vehicle's four-wheel drive transfer case housing, corresponding to a suitable position on the input bearing. This position is the primary transmission path for power input and internal gear excitation, and can most sensitively capture the vibration characteristics of the input shaft system. The second vibration acceleration sensor is arranged at a suitable position on the connecting plate connected to the drive dynamometer. This position is the key interface for vibration transmission to the outside through the mounting structure, and the collected vibration data can be directly correlated with the strength of the structure-transmitted noise. Preferably, a triaxial vibration acceleration sensor is used to simultaneously measure vibrations in three mutually perpendicular directions at each measuring point. To unify data description and analysis, the following coordinate system can be defined: the X-direction, parallel to the input / output axis of the four-wheel drive transfer case, is defined as axial; the Y-direction, in the horizontal plane, perpendicular to the X-direction, pointing to the left and right sides of the four-wheel drive transfer case, is defined as lateral; and the Z-direction, perpendicular to the XY plane, pointing to the top and bottom of the four-wheel drive transfer case, is defined as vertical. This coordinate definition ensures that vibration data from different measuring points and different components have consistent physical meaning and comparability.

[0059] Multiple sound sensors 1 are arranged in the key acoustic radiation area around the four-wheel drive transfer case, and the vertical distance between each sound sensor and the smooth outer surface of the four-wheel drive transfer case housing is specified as a fixed standard value, i.e., a first preset distance (e.g., 300 mm ± 10 mm), to ensure that each test is conducted under the same acoustic near-field conditions, allowing for direct comparison of the measured sound pressure level data. The sound sensors should be perpendicularly pointed to the geometric center of this outer surface. Preferably, a measuring point is arranged above the geometric center of the transfer case to measure its main radiated noise and capture the core acoustic characteristics of the transfer case.

[0060] This allows for the specific and standardized setting of measurement point locations, sensor selection, coordinate systems, and measurement distances, forming a complete, rigorous, and standardized NVH data acquisition scheme. This provides a reliable data foundation for the subsequent accurate analysis of vibration and noise data and the objective evaluation of transfer case NVH performance.

[0061] In some embodiments of this application, generating NVH test results for a vehicle four-wheel drive transfer case based on a preset test strategy, vibration information, and sound information includes: parsing the preset test strategy to obtain state information of the vehicle four-wheel drive transfer case; analyzing the vibration information based on a first preset analysis frequency to obtain target vibration data; analyzing the sound information based on a second preset analysis frequency to obtain target sound data, wherein the second preset analysis frequency is greater than the first preset analysis frequency; and generating NVH test results for the vehicle four-wheel drive transfer case based on the state information, target vibration data, and target sound data, wherein the NVH test results include a sound vibration spectrum. The first and second preset analysis frequencies can be calibrated according to actual conditions.

[0062] Specifically, given that structural vibration energy is typically concentrated in the low to mid-frequency range, an appropriate first preset analysis frequency (e.g., 6400 Hz) can be set. This frequency should cover the structural vibration modes and excitation frequencies of the transfer case under test. Considering that airborne noise, especially gear squealing and airflow noise, may contain very high frequency components (up to 20000 Hz or higher, the upper limit of the human audible range), a higher second preset analysis frequency (e.g., 25600 Hz) can be set. This frequency needs to be greater than the first preset analysis frequency to ensure that any possible high-frequency noise components can be captured.

[0063] First, the preset test strategy is decoded and time-series analyzed to extract state information directly related to the transfer case's operation. This information forms the core benchmark for subsequent data correlation analysis. The analysis process requires precise matching of operating condition parameter records during test execution to ensure the extracted state information matches the actual transfer case operating state during testing. This avoids parameter deviations between the preset strategy and actual operation, laying the foundation for accurate correlation between target vibration data, target sound data, and operating conditions. Next, signal analysis (such as Fourier transform and order analysis) is performed on the original vibration information based on a first preset analysis frequency to obtain target vibration data. Then, signal analysis is performed on the original sound information based on a second preset analysis frequency. This process typically includes A-weighted sound pressure level calculation, narrowband spectrum analysis, and order noise extraction to obtain target sound data. Finally, the extracted state information is fused with the target vibration data and target sound data to establish a three-dimensional correlation model of state parameters, vibration characteristics, and noise characteristics, ultimately generating NVH test results containing the sound vibration spectrum. For example, by fusing the four-wheel drive operating condition with speed difference (status information) with the vibration spectrum (target vibration data) and noise spectrum (target sound data) under that condition, a comprehensive NVH analysis chart for that condition can be generated. The sound vibration spectrum can visually present the correspondence between vibration and noise at different frequencies, helping to quickly locate the source of NVH problems (e.g., if the vibration and noise amplitudes both exceed the standard at a certain frequency, the component corresponding to that frequency can be identified as the core problem source). Simultaneously, the test results can also include comparisons of NVH performance under different operating conditions, statistical analysis of key NVH parameters, etc., providing a comprehensive basis for transfer case performance optimization.

[0064] In some embodiments of this application, the status information includes one or more of the following: load input, load output, operating condition, input speed, output speed, input torque, clutch clamping force, and slip torque of the vehicle's four-wheel drive transfer case.

[0065] Specifically, load input refers to the mechanical load borne by the input end of the transfer case, applied by the drive dynamometer, while load output refers to the mechanical load transmitted from the output end of the transfer case to the test drive axle and the load dynamometer. Both directly reflect the power transmission load state of the transfer case. Different loads correspond to different meshing and operating forces of internal gears and bearings, leading to differences in vibration and noise characteristics, which is an important basis for linking NVH data with load state. Operating condition is a precise definition of the core working mode of the transfer case, which may include rear-wheel drive mode, four-wheel drive mode without speed difference, four-wheel drive mode with speed difference, forward drive uniform acceleration mode, reverse drag uniform deceleration mode, steady-state operating mode, etc. Different operating conditions correspond to different power distribution logic and internal motion states of the transfer case, such as clutch engagement / disengagement, presence or absence of speed difference, etc., which are the core benchmarks for dividing NVH data analysis dimensions, ensuring that the NVH performance of the transfer case can be evaluated in a targeted manner under different actual use scenarios. Input speed refers to the rotational speed of the input end of the transfer case controlled by the drive dynamometer, while output speed refers to the rotational speed transmitted from each output end of the transfer case to the test drive axle 5. Rotational speed is the core factor affecting the vibration and noise frequency of the transfer case. Gear meshing frequency is positively correlated with rotational speed, and the difference between the two, i.e., the speed difference, directly determines the clutch slippage state. It is a key parameter for conducting order analysis and correlating rotational speed with NVH characteristics. Input torque refers to the torque applied by the driving dynamometer to the input end of the transfer case, determining the meshing tightness and force magnitude of the internal transmission components. The greater the input torque, the greater the meshing / operating load on the gears and bearings, and the higher the vibration and noise amplitude, making it a core basis for analyzing the relationship between load and NVH performance. Clutch clamping force and slippage torque are applicable to four-wheel drive transfer cases with multi-plate clutches and are core parameters reflecting the clutch's working state. Clutch clamping force determines the degree of clutch engagement; sufficient clamping force results in complete clutch engagement without slippage, while insufficient clamping force leads to slippage. Slippage torque directly reflects the magnitude of the frictional torque during clutch slippage. Both are related to transfer case slippage noise, chatter, and other unique NVH problems, and are key bases for specific analysis of clutch NVH performance.

[0066] In actual testing, one or more of the above-mentioned state information can be selected for correlation analysis with NVH data according to the specific test target. For example, when analyzing clutch slippage noise, focus on correlation between clutch clamping force, slippage torque, speed difference and target sound data; when analyzing gear meshing noise under different loads, focus on correlation between input torque, load input and output and target vibration data to ensure the relevance and accuracy of the analysis.

[0067] As a specific embodiment of this application, such as Figure 4 As shown, the NVH testing method for a vehicle's four-wheel drive transfer case may include the following steps: S101, build a test bench, including installing a drive dynamometer, a load dynamometer, a test drive axle, a subframe and a drive shaft. Place the core components in an anechoic chamber, isolate the high-noise load dynamometer outdoors and connect it through an acoustic through-wall shaft.

[0068] S102, a vibration acceleration sensor and a sound sensor are arranged at preset positions on the vehicle's four-wheel drive transfer case, wherein the preset positions include positions on the vehicle's four-wheel drive transfer case and positions around the vehicle's four-wheel drive transfer case.

[0069] S103, Obtain the preset test strategy for the vehicle's four-wheel drive transfer case. Specifically, as shown in the table below.

[0070]

[0071] S104, according to the preset test strategy, controls the load dynamometer and drive dynamometer respectively, so as to obtain the vibration information and sound information of the vehicle's four-wheel drive transfer case through the vibration acceleration sensor and the sound sensor respectively.

[0072] S105 analyzes the preset test strategy to obtain the status information of the vehicle's four-wheel drive transfer case.

[0073] S106, The vibration information is analyzed based on the first preset analysis frequency to obtain the target vibration data.

[0074] S107, The sound information is analyzed based on the second preset analysis frequency to obtain the target sound data, wherein the second preset analysis frequency is greater than the first preset analysis frequency.

[0075] S108 generates NVH test results for the vehicle's four-wheel drive transfer case based on status information, target vibration data, and target sound data. Specifically, as follows... Figure 5 As shown, the test results show a relatively consistent trend, and the test repeatability is good, which can be used for subsequent development and verification of passenger vehicle four-wheel drive transfer cases.

[0076] In summary, the NVH testing method for a vehicle four-wheel drive transfer case according to the embodiments of this application firstly arranges vibration acceleration sensors and sound sensors at preset positions on the vehicle four-wheel drive transfer case, including positions on the transfer case itself and positions around the transfer case. Then, a preset testing strategy for the vehicle four-wheel drive transfer case is obtained. Next, a load dynamometer and a drive dynamometer are controlled according to the preset testing strategy to acquire vibration and sound information of the vehicle four-wheel drive transfer case through the vibration acceleration sensors and sound sensors, respectively. Finally, based on the preset testing strategy, vibration information, and sound information, the NVH test results of the vehicle four-wheel drive transfer case are generated. Therefore, it is possible to accurately collect vibration and sound data of the four-wheel drive transfer case through bench testing, and generate NVH results by combining the test strategy, providing data support for improving overall vehicle comfort.

[0077] Corresponding to the above embodiments, this application also proposes an NVH testing device for a vehicle four-wheel drive transfer case.

[0078] like Figure 6 As shown, the NVH testing device 600 for a vehicle four-wheel drive transfer case according to an embodiment of this application includes: a layout module 610, an acquisition module 620, a control module 630, and a generation module 640.

[0079] The arrangement module 610 is used to arrange vibration acceleration sensors and sound sensors at preset positions on the vehicle's four-wheel drive transfer case, including positions on the vehicle's four-wheel drive transfer case and positions around the vehicle's four-wheel drive transfer case; the acquisition module 620 is used to acquire a preset test strategy for the vehicle's four-wheel drive transfer case; the control module 630 is used to control the load dynamometer and drive dynamometer according to the preset test strategy to acquire vibration information and sound information of the vehicle's four-wheel drive transfer case through the vibration acceleration sensors and sound sensors respectively; and the generation module 640 is used to generate NVH test results for the vehicle's four-wheel drive transfer case based on the preset test strategy, vibration information, and sound information.

[0080] According to one embodiment of this application, the test bench further includes a drive axle input drive shaft, a drive axle output drive shaft, a test drive axle, and a subframe. The vehicle's four-wheel drive transfer case is mounted on the drive dynamometer via a connecting plate. The input end of the vehicle's four-wheel drive transfer case is connected to the main shaft of the drive dynamometer. The first output end of the vehicle's four-wheel drive transfer case is connected to the input end of the test drive axle via the drive axle input drive shaft. The output end of the test drive axle is connected to the load dynamometer via the drive axle output drive shaft. The test drive axle is mounted on the subframe.

[0081] According to one embodiment of this application, the output end of the test drive bridge includes a first output end and a second output end, the load dynamometer includes a first load dynamometer and a second load dynamometer, and the drive bridge output transmission shaft includes a first drive bridge output transmission shaft and a second drive bridge output transmission shaft. The first output end of the test drive bridge is connected to the first load dynamometer through the first drive bridge output transmission shaft, and the second output end of the test drive bridge is connected to the second load dynamometer through the second drive bridge output transmission shaft.

[0082] According to one embodiment of this application, the test bench further includes an anechoic chamber, in which the vehicle four-wheel drive transfer case, drive dynamometer, drive axle input drive shaft, drive axle output drive shaft, auxiliary drive axle and subframe are all disposed. The load dynamometer is disposed outside the anechoic chamber and is connected to the drive axle output drive shaft via a through-wall shaft and intermediate support.

[0083] According to one embodiment of this application, the vibration acceleration sensor includes a first vibration acceleration sensor and a second vibration acceleration sensor, and multiple sound sensors are provided. The first vibration acceleration sensor is disposed at the input end of the vehicle's four-wheel drive transfer case, and the second vibration acceleration sensor is disposed at the connecting plate. The multiple sound sensors are respectively disposed around the vehicle's four-wheel drive transfer case, wherein the vertical distance between the sound sensors and the housing of the vehicle's four-wheel drive transfer case is a first preset distance.

[0084] According to one embodiment of this application, the generation module 640 is specifically used to generate NVH test results for a vehicle four-wheel drive transfer case based on a preset test strategy, vibration information, and sound information. This includes: parsing the preset test strategy to obtain state information of the vehicle four-wheel drive transfer case; analyzing the vibration information based on a first preset analysis frequency to obtain target vibration data; analyzing the sound information based on a second preset analysis frequency to obtain target sound data, wherein the second preset analysis frequency is greater than the first preset analysis frequency; and generating NVH test results for the vehicle four-wheel drive transfer case based on the state information, target vibration data, and target sound data, wherein the NVH test results include a sound vibration spectrum.

[0085] According to one embodiment of this application, the status information includes one or more of the following for the vehicle's four-wheel drive transfer case: load input, load output, operating condition, input speed, output speed, input torque, clutch clamping force, and slip torque.

[0086] It should be noted that the above-described embodiments and explanations of the beneficial effects of the NVH test method for vehicle four-wheel drive transfer cases also apply to the NVH test device for vehicle four-wheel drive transfer cases in the embodiments of this application. To avoid redundancy, they will not be elaborated in detail here.

[0087] In summary, the NVH testing device for a vehicle four-wheel drive transfer case according to the embodiments of this application first arranges vibration acceleration sensors and sound sensors at preset positions on the vehicle four-wheel drive transfer case using an arrangement module. These preset positions include those on the vehicle four-wheel drive transfer case and those around it. Then, an acquisition module acquires a preset testing strategy for the vehicle four-wheel drive transfer case. Next, a control module controls the load dynamometer and drive dynamometer according to the preset testing strategy to acquire vibration and sound information from the vehicle four-wheel drive transfer case through the vibration acceleration sensors and sound sensors, respectively. Finally, a generation module generates the NVH test results for the vehicle four-wheel drive transfer case based on the preset testing strategy, vibration information, and sound information. Therefore, it is possible to accurately collect vibration and sound data of the four-wheel drive transfer case through bench testing, and generate NVH results by combining the test strategy, providing data support for improving overall vehicle comfort.

[0088] Corresponding to the above embodiments, this application also proposes an electronic device.

[0089] like Figure 7 As shown, the electronic device 700 of this application embodiment includes a memory 710, a processor 720, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement any of the above-mentioned NVH test methods for vehicle four-wheel drive transfer cases.

[0090] According to the electronic device in the application embodiment, when the processor executes the computer program, it implements any of the above-mentioned NVH testing methods for vehicle four-wheel drive transfer cases, realizes the accurate acquisition of vibration and sound data of the four-wheel drive transfer case through bench testing, and generates NVH results in combination with the testing strategy, providing data support for improving the overall vehicle comfort.

[0091] Corresponding to the above embodiments, this application also proposes a computer-readable storage medium.

[0092] The computer-readable storage medium of this application embodiment stores a computer program that is executed by a processor to implement any of the above-described NVH test methods for a vehicle four-wheel drive transfer case.

[0093] According to the embodiments of this application, a computer-readable storage medium storing a computer program thereon implements any of the above-mentioned NVH testing methods for a vehicle four-wheel drive transfer case when executed by a processor. This method enables the accurate acquisition of vibration and sound data of the four-wheel drive transfer case through bench testing, and generates NVH results by combining the test strategy, thus providing data support for improving the overall vehicle comfort.

[0094] Specifically, in the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0095] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0096] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for testing the NVH (Noise, Vibration, and Harshness) of a vehicle's four-wheel drive transfer case, characterized in that, The vehicle's four-wheel drive transfer case is mounted on a test bench, which includes a load dynamometer and a drive dynamometer. The method includes: Vibration acceleration sensors and sound sensors are respectively arranged at preset positions on the vehicle's four-wheel drive transfer case, wherein the preset positions include positions on the vehicle's four-wheel drive transfer case and positions around the vehicle's four-wheel drive transfer case; Obtain the preset test strategy for the vehicle's four-wheel drive transfer case; The load dynamometer and the drive dynamometer are controlled according to the preset test strategy to obtain the vibration information and sound information of the vehicle four-wheel drive transfer case through the vibration acceleration sensor and the sound sensor, respectively. Based on the preset test strategy, the vibration information, and the sound information, the NVH test results of the vehicle's four-wheel drive transfer case are generated.

2. The NVH testing method for a vehicle four-wheel drive transfer case according to claim 1, characterized in that, The test bench also includes a drive axle input drive shaft, a drive axle output drive shaft, a test drive axle, and a subframe. The vehicle four-wheel drive transfer case is mounted on the drive dynamometer via a connecting plate. The input end of the vehicle four-wheel drive transfer case is connected to the main shaft of the drive dynamometer. The first output end of the vehicle four-wheel drive transfer case is connected to the input end of the test drive axle via the drive axle input transmission shaft. The output end of the auxiliary test drive axle is connected to the load dynamometer via the drive axle output transmission shaft, wherein the auxiliary test drive axle is mounted on the subframe.

3. The NVH testing method for a vehicle four-wheel drive transfer case according to claim 2, characterized in that, The output terminals of the test drive axle include a first output terminal and a second output terminal; the load dynamometer includes a first load dynamometer and a second load dynamometer; and the drive axle output drive shaft includes a first drive axle output drive shaft and a second drive axle output drive shaft. The first output end of the test drive bridge is connected to the first load dynamometer via the first drive bridge output transmission shaft, and the second output end of the test drive bridge is connected to the second load dynamometer via the second drive bridge output transmission shaft.

4. The NVH testing method for a vehicle four-wheel drive transfer case according to claim 2, characterized in that, The test bench also includes an anechoic chamber, in which the vehicle four-wheel drive transfer case, the drive dynamometer, the drive axle input drive shaft, the drive axle output drive shaft, the auxiliary drive axle, and the subframe are all housed. The load dynamometer is housed outside the anechoic chamber and is connected to the drive axle output drive shaft via a through-wall shaft and an intermediate support.

5. The NVH testing method for a vehicle four-wheel drive transfer case according to claim 2, characterized in that, The vibration acceleration sensor includes a first vibration acceleration sensor and a second vibration acceleration sensor, and there are multiple sound sensors, among which... The first vibration acceleration sensor is located at the input end of the vehicle's four-wheel drive transfer case, and the second vibration acceleration sensor is located at the coupling plate. Multiple sound sensors are respectively disposed around the vehicle's four-wheel drive transfer case, wherein the vertical distance between the sound sensors and the housing of the vehicle's four-wheel drive transfer case is a first preset distance.

6. The NVH testing method for a vehicle four-wheel drive transfer case according to claim 1, wherein generating the NVH test result of the vehicle four-wheel drive transfer case based on the preset test strategy, the vibration information, and the sound information includes: The preset test strategy is analyzed to obtain the status information of the vehicle's four-wheel drive transfer case; The vibration information is analyzed based on a first preset analysis frequency to obtain target vibration data; The sound information is analyzed based on a second preset analysis frequency to obtain target sound data, wherein the second preset analysis frequency is greater than the first preset analysis frequency. Based on the state information, the target vibration data, and the target sound data, the NVH test results of the vehicle's four-wheel drive transfer case are generated, wherein the NVH test results include the sound vibration spectrum.

7. The NVH testing method for a vehicle four-wheel drive transfer case according to claim 6, characterized in that, The status information includes one or more of the following for the vehicle's four-wheel drive transfer case: load input, load output, operating condition, input speed, output speed, input torque, clutch clamping force, and slip torque.

8. An NVH testing device for a vehicle four-wheel drive transfer case, characterized in that, The vehicle's four-wheel drive transfer case is mounted on a test bench, which includes a load dynamometer and a drive dynamometer. The device includes: The module is used to place a vibration acceleration sensor and a sound sensor at preset positions on the vehicle's four-wheel drive transfer case, wherein the preset positions include positions on the vehicle's four-wheel drive transfer case and positions around the vehicle's four-wheel drive transfer case. The acquisition module is used to acquire the preset test strategy of the vehicle's four-wheel drive transfer case; The control module is used to control the load dynamometer and the drive dynamometer according to the preset test strategy, so as to obtain the vibration information and sound information of the vehicle four-wheel drive transfer case through the vibration acceleration sensor and the sound sensor, respectively. The generation module is used to generate NVH test results for the vehicle's four-wheel drive transfer case based on the preset test strategy, the vibration information, and the sound information.

9. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the NVH test method for a vehicle four-wheel drive transfer case as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the NVH test method for a vehicle four-wheel drive transfer case as described in any one of claims 1-7.

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