A method for selecting a vibration point for EOL testing of a transmission assembly

Abstract

The application provides a transmission assembly EOL test vibration point selection method, comprising the following steps: S1, arranging two microphone sensors at the left ear and the right ear of the driver's seat in an electric vehicle; installing multiple same-specification transmission assemblies on the electric vehicle to obtain different test vehicles; selecting multiple vibration points on the transmission assembly housings of the test vehicles and installing vibration sensors on the vibration points, and the positions of the vibration points on each transmission assembly correspond to each other; S2, operating each test vehicle under the same working condition to obtain the binaural masking values of each test vehicle and the housing vibration excitation amplitudes at different vibration points in each test vehicle; S3, performing linear regression analysis on the binaural masking values of different test vehicles and the housing vibration excitation amplitudes at the same vibration points on different test vehicles to obtain the determination coefficients at each vibration point, and taking the vibration point with the largest determination coefficient as the transmission assembly EOL test vibration point to avoid the problem of inaccurate EOL test evaluation caused by inaccurate test vibration point position.

Description

Technical Field

[0001] This invention belongs to the field of EOL testing technology, specifically relating to a method for selecting vibration points for EOL testing of a transmission assembly. Background Technology

[0002] With the increasing prominence of environmental pollution and the energy crisis, pure electric vehicles have been widely used. However, due to the significant differences in the basic structure and working principle between electric vehicles and traditional fuel vehicles, and the absence of the "masking effect" of an engine, some noise problems caused by the power transmission system of electric vehicles have become particularly prominent, such as gear squealing in the transmission, which greatly reduces the ride comfort of the driver.

[0003] The whistling sound from the transmission is caused by the meshing vibration of the transmission gear pairs, which is transmitted to the transmission housing, causing the housing to vibrate and radiate noise. During manufacturing, each transmission assembly undergoes end-of-line (EOL) testing to ensure its vibration and radiated noise levels are within acceptable limits. However, radiated noise testing requires a semi-anechoic environment, which is costly and impractical for large-scale production. Currently, only the transmission housing vibration excitation is tested on an EOL test bench to assess the whistling sound. However, the vibration excitation varies at different locations on the transmission housing, resulting in different whistling sounds and an inaccurate description of the whistling sound level inside the vehicle. Therefore, determining the appropriate EOL test vibration point for the transmission assembly to accurately assess the whistling sound inside the vehicle is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for selecting vibration points for EOL testing of transmission assembly. This method analyzes the linear correlation between the in-vehicle binaural masking value and the vibration excitation amplitude of the housing at different vibration points, determines the vibration point with the highest correlation, and uses it as the EOL testing vibration point for transmission assembly, thus avoiding the problem of inaccurate assessment of in-vehicle howling level caused by improper selection of testing vibration points.

[0005] To achieve the above and other related objectives, the present invention provides a method for evaluating the order of whistling in electric vehicles, the method comprising the following steps:

[0006] S1. Two microphone sensors are placed at the left ear and right ear of the driver's seat in the electric vehicle; multiple transmission assemblies of the same specifications are installed on the electric vehicle to obtain different test vehicles; multiple vibration points are selected on the transmission assembly housing of each test vehicle to install vibration sensors, and the selected vibration points on each transmission assembly correspond one-to-one.

[0007] S2. Run test vehicles equipped with different transmission assemblies under the same operating conditions to obtain the binaural masking value ΔLp of each test vehicle and the shell vibration excitation amplitude G at different vibration points inside each test vehicle. dB ;

[0008] S3. Perform linear regression analysis on the binaural masking values ​​of different test vehicles and the shell vibration excitation amplitude at the same vibration point on different test vehicles to obtain the determination coefficient R at each vibration point. 2 By comparing the magnitudes of the determination coefficients at each vibration point, the vibration point with the largest determination coefficient is taken as the EOL test vibration point of the transmission assembly.

[0009] Preferably, the method for obtaining the binaural masking value ΔLp of each test vehicle includes the following steps:

[0010] The sound signals collected by each microphone sensor inside the test vehicle are processed to obtain the order sound pressure level and background sound pressure level of each sound signal; the order sound pressure level is the octave band bandwidth A-weighted sound pressure level. The background sound pressure level is a 1 / 3 octave bandwidth A-weighted sound pressure level.

[0011] Based on the order sound pressure level and background sound pressure level of each sound signal inside the test vehicle, the masking value ΔL at each microphone sensor location on the test vehicle was calculated. t ;

[0012] The root mean square value of each masking value on the test vehicle is processed to obtain the corresponding binaural masking value ΔLp of the test vehicle.

[0013] Preferably, the vibration excitation amplitude G of the shell at different vibration points on the test vehicle is... dB The method for obtaining it includes the following steps:

[0014] Based on the vibration signals collected by various vibration sensors inside the test vehicle, the transmission order vibration displacement V1 at each vibration point inside the test vehicle is obtained.

[0015] Calculate the excitation amplitude G of the shell vibration at different vibration points on the test vehicle. dB The calculation formula is:

[0016]

[0017] V0 is the vibration reference value, which is determined by the user.

[0018] Preferably, the vibration sensor is an acceleration vibration sensor or a displacement vibration sensor.

[0019] Preferably, the test vehicle operates at a constant speed of 80 km / h.

[0020] Preferably, the bandwidth of the octave band bandwidth sound pressure level is 0.2.

[0021] As described above, the method for selecting vibration points for EOL testing of a transmission assembly according to the present invention has the following beneficial effects:

[0022] This invention obtains the linear regression determination coefficient R0 at each vibration point by performing linear regression analysis on the binaural masking values ​​on different test vehicles and the vibration excitation amplitude of the shell at the same vibration point on different test vehicles. 2 To determine the vibration point with the highest correlation between the dual-ear masking value and the housing vibration excitation amplitude, this vibration point is used as the EOL test vibration point for the transmission assembly, improving the accuracy of the housing vibration excitation amplitude test and laying the foundation for accurate assessment of the transmission whine level in the vehicle. Two microphone sensors are installed at the left and right ear positions of the driver's seat, making the acquired sound signals more comprehensive and more consistent with the actual situation, further improving the accuracy of the EOL test vibration point selection. Attached Figure Description

[0023] Figure 1 This is a flowchart of the method for selecting vibration points for EOL testing of the transmission assembly according to the present invention.

[0024] Figure 2 A schematic diagram showing the microphone sensor positioned on the driver's seat.

[0025] Figure 3 This is a linear regression analysis diagram showing the binaural masking values ​​of different test vehicles and the vibration excitation amplitude of the shell at vibration point 1 on different test vehicles in this invention.

[0026] Figure 4 This is a linear regression analysis diagram showing the binaural masking values ​​of different test vehicles and the vibration excitation amplitude of the shell at vibration point 2 on different test vehicles in this invention.

[0027] Figure 5 This is a linear regression analysis diagram showing the binaural masking values ​​of different test vehicles and the vibration excitation amplitude of the shell at vibration point 3 on different test vehicles in this invention.

[0028] Figure 6 This is a linear regression analysis diagram showing the binaural masking values ​​of different test vehicles and the vibration excitation amplitude of the shell at vibration point 4 on different test vehicles in this invention. Detailed Implementation

[0029] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0030] Please see Figures 1 to 6It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0031] like Figure 1 As shown, this embodiment of the invention provides a method for selecting vibration points for EOL testing of a transmission assembly, the method comprising the following steps:

[0032] S1. Two microphone sensors are placed at the left ear and right ear of the driver's seat in the electric vehicle; multiple transmission assemblies of the same specifications are installed on the electric vehicle in sequence to obtain different test vehicles; multiple vibration points are selected on the housing of the transmission assembly on each test vehicle to install vibration sensors, and the selected vibration points on each transmission assembly correspond one-to-one.

[0033] Specifically, such as Figure 2 As shown, four microphone sensors are installed on the driver's seat of the electric vehicle, forming a rectangular array of microphones. The four microphone sensors include microphone sensor 11 and microphone sensor 12 located at the left ear position of the driver's seat, and microphone sensor 13 and microphone sensor 14 located at the right ear position of the driver's seat. Each microphone sensor transmits the collected data to the data display 2, which is connected to the data processor 3. The data processor 3 is preferably a laptop or desktop computer.

[0034] Six transmission assemblies are preferably installed, and they are sequentially mounted on electric vehicles to obtain six test vehicles. According to the installation order of the transmission assemblies, the six test vehicles are Test Vehicle 1, Test Vehicle 2, Test Vehicle 3, Test Vehicle 4, Test Vehicle 5, and Test Vehicle 6. Each transmission assembly housing has four vibration points, namely vibration point 1, vibration point 2, vibration point 3, and vibration point 4. The selection principle of vibration points includes: located on a plane and close to the gear meshing position.

[0035] It is understood that the vibration sensor installed at the vibration point can be an acceleration vibration sensor or a displacement vibration sensor, and there is no limitation on this. In this embodiment, an acceleration vibration sensor is preferred.

[0036] S2. Run test vehicles equipped with different transmission assemblies under the same operating conditions to obtain the binaural masking value ΔLp of each test vehicle and the shell vibration excitation amplitude G at different vibration points inside each test vehicle. dB ;

[0037] In this invention, the operating condition of the test vehicle refers to the condition of traveling at a constant speed of v0, where v0 ≤ 80 km / h. In this embodiment, v0 is preferably set to 80 km / h.

[0038] Since the binaural masking value ΔLp is obtained using the same method for all test vehicles, we will now take one of the test vehicles as an example to explain in detail the method for obtaining the binaural masking value ΔLp for each test vehicle:

[0039] (1) The sound signals collected by each microphone sensor in the test vehicle are processed to obtain the order sound pressure level and background sound pressure level of each sound signal; the order sound pressure level is the octave band bandwidth A-weighted sound pressure level. The background sound pressure level is a 1 / 3 octave bandwidth A-weighted sound pressure level.

[0040] Specifically, octave bandwidth A-weighted sound pressure level The calculation formula is as follows:

[0041]

[0042] Where, N a This represents the total number of measurement points.

[0043] L Pi，tonedband Let be the octave band bandwidth A-weighted sound level measured at point i;

[0044] 1 / 3 octave bandwidth sound pressure level The calculation formula is as follows:

[0045]

[0046] Where, N a This represents the total number of measurement points.

[0047] L Pi，1 / 3toneband The A-weighted sound level with a 1 / 3 octave bandwidth measured at point i;

[0048] (2) Based on the order sound pressure level and background sound pressure level of each sound signal inside the test vehicle, the masking value ΔL at each microphone sensor location on the test vehicle is calculated. t ;

[0049] Specifically, the masking value ΔL at the location of microphone sensor 11 can be calculated using formulas (1) to (3). t1The masking value ΔL at position 12 of microphone sensor number 2 t2 The masking value ΔL at position 13 of microphone sensor number 3 t3 and the masking value ΔL at position 14 of microphone sensor number 4 t4 ;

[0050] (3) Perform root mean square processing on each masking value on the test vehicle to obtain the binaural masking value ΔLp of the test vehicle;

[0051] Specifically, the formula for calculating the binaural masking value ΔLp is:

[0052]

[0053] The binaural masking values ​​of each test vehicle were calculated using formulas (1) to (4), and the results are shown in Table 1.

[0054] Table 1. Binaural masking values ​​for each test vehicle.

[0055] test vehicle Binaural masking value Test vehicle 1 7.1 Test vehicle 2 5.2 Test vehicle 3 4.1 Test vehicle 4 3.3 Test vehicle 5 1.2 Test vehicle 6 0

[0056] Due to the excitation amplitude G of the shell vibration at each vibration point dB The method for obtaining the values ​​is the same. Taking any vibration point on any test vehicle as an example, we will specifically explain the shell vibration excitation amplitude G at each vibration point on each test vehicle. dB How to obtain:

[0057] Based on the vibration signals collected by each vibration sensor, the gearbox order vibration displacement V1 at the corresponding vibration point is obtained, and then the vibration excitation amplitude G of the housing at each vibration point is calculated. dB The calculation formula is:

[0058]

[0059] Wherein, V0 is the vibration reference value, the value of which is determined by the user, and is generally 1×10. -5 ;

[0060] Since the vibration sensor installed in this embodiment is a vibration acceleration sensor, the vibration signal it collects is vibration acceleration. It is necessary to perform two integration operations on the vibration acceleration to obtain the order vibration displacement V1 of the transmission.

[0061] Using formula (5), the vibration excitation amplitude G of the shell at different vibration points on different test vehicles was calculated. dB The calculation results are shown in Table 2.

[0062] Table 2. Vibration excitation amplitude of the shell at different vibration points on different test vehicles.

[0063]

[0064] S3. Perform linear regression analysis on the binaural masking values ​​of different test vehicles and the shell vibration excitation amplitude at the same vibration point on different test vehicles to obtain the determination coefficient R at each vibration point. 2 By comparing the magnitudes of the determination coefficients at each vibration point, the vibration point with the largest determination coefficient is taken as the EOL test vibration point of the transmission assembly.

[0065] Specifically, using the masking value of the two ears as the X-axis and the vibration excitation amplitude of the shell at the same vibration point as the ordinate, linear regression analysis was performed using software such as Excel, MATLAB, and SPSS to obtain the determination coefficient R at each vibration point. 2 In this embodiment, linear regression analysis is preferably performed using Excel software to obtain the linear regression analysis graphs for vibration points 1 to 4, as shown below. Figures 3 to 6 As shown, the dashed lines represent the fitted straight lines, and the solid lines represent the actual lines connecting the points. Figures 3 to 6 The regression analysis determined the coefficients of determination R1 for vibration points 1 to 4. 2 The coefficients were 0.9846, 0.5058, 0.0256, and 0.5899, respectively. It was found that the coefficient of determination was the largest at vibration point 1, indicating that the dual-ear masking value at vibration point 1 was most correlated with the vibration excitation amplitude of the housing. Therefore, vibration point 1 is the vibration point for EOL testing of the transmission assembly.

[0066] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for selecting vibration points for EOL (End-of-Life) testing of a transmission assembly, characterized in that, The method includes the following steps: S1. Two microphone sensors are placed at the left ear and right ear of the driver's seat in the electric vehicle; multiple transmission assemblies of the same specifications are installed on the electric vehicle to obtain different test vehicles; multiple vibration points are selected on the transmission assembly housing of each test vehicle to install vibration sensors, and the selected vibration points on each transmission assembly correspond one-to-one. S2. Run test vehicles equipped with different transmission assemblies under the same operating conditions to obtain the binaural masking value ΔLp of each test vehicle and the shell vibration excitation amplitude G at different vibration points inside each test vehicle. dB ; S3. Perform linear regression analysis on the binaural masking values ​​of different test vehicles and the shell vibration excitation amplitude at the same vibration point on different test vehicles to obtain the determination coefficient R at each vibration point. 2 Compare the magnitudes of the determination coefficients at each vibration point, and take the vibration point with the largest determination coefficient as the EOL test vibration point of the transmission assembly. The method for obtaining the binaural masking value ΔLp for each test vehicle includes the following steps: The sound signals collected by the various microphone sensors inside the test vehicle are processed to obtain the order sound pressure level and background sound pressure level of each sound signal; the order sound pressure level is the octave band bandwidth A-weighted sound pressure level. The background sound pressure level is a 1 / 3 octave bandwidth A-weighted sound pressure level. Based on the order sound pressure level and background sound pressure level of each sound signal inside the test vehicle, the masking value ΔL at each microphone sensor location on the test vehicle was calculated. t ; The root mean square value of each masking value on the test vehicle is processed to obtain the corresponding binaural masking value ΔLp of the test vehicle.

2. The method for selecting vibration points for EOL testing of a transmission assembly according to claim 1, characterized in that, The amplitude of the shell vibration excitation G at different vibration points on the test vehicle dB The method for obtaining it includes the following steps: Based on the vibration signals collected by various vibration sensors inside the test vehicle, the transmission order vibration displacement V1 at each vibration point inside the test vehicle is obtained. Calculate the excitation amplitude G of the shell vibration at different vibration points on the test vehicle. dB The calculation formula is: V0 is the vibration reference value, which is determined by the user.

3. The method for selecting vibration points for EOL testing of a transmission assembly according to claim 1, characterized in that, The vibration sensor is an acceleration vibration sensor or a displacement vibration sensor.

4. The method for selecting vibration points for EOL testing of a transmission assembly according to claim 1, characterized in that, The test vehicle was to operate at a constant speed of 80 km / h.

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