Decibel calculation method for tire structure sound

Abstract

The invention provides a decibel calculation method for tire structure sound, and solves the problems that data acquisition is carried out in a specific environment or a limited speed range in most existing tire noise test methods, and a data analysis means is relatively single; the influence rule of the vibration characteristics of the tire in different frequency ranges on the in-vehicle noise cannot be fully captured, and the device can be widely applied to the field of tire testing. The method specifically comprises the following steps: uniformly reducing the speed of a tire from a high-speed rotating state to a low-speed rotating state, and collecting a vibration signal in the speed reduction process; preprocessing the vibration signal to obtain a frequency domain signal; obtaining frequency domain signal effective values of the frequency domain signals at low and medium frequencies on the X axis, the Y axis and the Z axis; and establishing a decibel calculation model according to the frequency domain signal effective value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tire testing, and particularly relates to a decibel calculation method for tire structure sound. BACKGROUND

[0002] During the driving of an automobile, as a key component for contacting the ground, the structure sound characteristics of a tire have an important influence on the noise level in the automobile. The traditional evaluation method for tire noise often has many limitations, and it is difficult to accurately and comprehensively reflect the actual contribution of the structure sound of the tire to the noise in the automobile. With the development of the automobile industry, consumers have increasingly strict requirements for the comfort in the automobile, especially noise control. Therefore, an effective method for evaluating the influence of the structure sound of the tire on the noise in the automobile is urgently needed, so as to optimize the design of the tire and the overall performance of the automobile. The existing tire noise test method mainly collects data in a specific environment or a limited speed range, and the data analysis means is relatively single, and the influence law of the vibration characteristics of the tire in different frequency ranges on the noise in the automobile cannot be fully captured. SUMMARY

[0003] The application aims to solve the above technical problems, and provides a decibel calculation method for tire structure sound.

[0004] To this end, the application provides a decibel calculation method for tire structure sound, comprising the following steps:

[0005] S10: uniformly decelerating the tire from a high-speed rotating state to a low-speed rotating state, and collecting vibration signals in the deceleration process;

[0006] S20: pre-processing the vibration signals to obtain frequency domain signals;

[0007] S30: obtaining effective values of the frequency domain signals in the middle and low frequencies on the X-axis, the Y-axis and the Z-axis;

[0008] S40: establishing a decibel calculation model according to the effective values of the frequency domain signals.

[0009] Further, the step of uniformly decelerating the tire from a high-speed rotating state to a low-speed rotating state and collecting vibration signals in the deceleration process is as follows:

[0010] The tire is installed on a high-speed uniformity test bench, the speed of the tire is uniformly decelerated from 80km / h to 40km / h, and the vibration signals of the tire are collected by using a tracking speed method.

[0011] Further, the step of pre-processing the vibration signals to obtain frequency domain signals is as follows:

[0012] The vibration signals are subjected to Fourier transform, and then subjected to average processing, so as to convert the vibration signals into frequency domain signals.

[0013] Furthermore, the steps for obtaining the effective values ​​of the frequency domain signal located at mid-to-low frequencies on the X, Y, and Z axes are as follows:

[0014] Obtain the effective values ​​in the frequency ranges of 60-180Hz and 180-260Hz in the X / Y / Z directions, and analyze the effective values.

[0015] Furthermore, based on the effective value of the frequency domain signal, the steps to establish a decibel calculation model are as follows:

[0016] Let the time functions of the forces in the X, Y, and Z directions at the wheel center obtained from the tire bench test be Fx(t), Fy(t), and Fz(t), respectively.

[0017] Performing Fourier transforms on the time functions of the forces in the X, Y, and Z directions yields their expressions in the frequency domain, namely Fx(ω), Fy(ω), and Fz(ω), where ω is the angular frequency;

[0018] Based on the structural dynamics characteristics of the vehicle, the transfer function matrix [H(ω)] from the wheel center to the vehicle interior noise is established;

[0019] The sound pressure frequency domain function P(ω) of the in-vehicle noise can be calculated using the following formula:

[0020]

[0021] The inverse Fourier transform of the sound pressure frequency domain function P(ω) yields the sound pressure time function P(t);

[0022] Calculate the effective value of the sound pressure time function P(t), and calculate the decibel value of the in-vehicle noise using the sound pressure level formula. ,

[0023]

[0024] in For reference sound pressure level.

[0025] This invention provides a method for calculating the decibel level of tire structural noise, which has the following beneficial effects:

[0026] It can accurately measure the acoustic characteristics of tire structure while covering a wider range of actual driving speeds, providing a more complete and detailed data foundation for tire structure acoustic optimization.

[0027] The data analysis method is scientific and rigorous. By using Fourier transform and averaging, combined with the analysis of RMS values ​​within a specific frequency range, it effectively improves the accuracy and reliability of the evaluation results. This helps automakers to accurately predict and control in-vehicle noise levels during tire selection and vehicle design, thereby improving vehicle comfort and meeting consumers' demands for a high-quality travel experience. Attached Figure Description

[0028] Figure 1 This is the tire spectrum diagram of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments to aid in understanding its content. Unless otherwise specified, the methods used in this invention are conventional methods; the raw materials and apparatus used, unless otherwise specified, are conventional commercially available products.

[0030] This invention provides a method for calculating the decibel level of tire structural noise, comprising the following steps:

[0031] Data Acquisition: Data was acquired using a tracking speed sampling method on a high-speed tire uniformity test bench, with the acquisition speed decreasing uniformly from 80 km / h to 40 km / h. Within this speed variation range, the tire's operating conditions cover a variety of common driving scenarios, effectively capturing vibration information generated by the tire at different speeds, providing comprehensive and representative raw data for subsequent analysis.

[0032] Data Analysis: Fourier transform and averaging were performed on the collected sampling signals. First, Fourier transform was used to convert the time-domain signal into a frequency-domain signal, thus clearly presenting the distribution of tire vibration signals across different frequency components. Then, averaging was performed to reduce random noise interference and improve data stability and reliability. Furthermore, the effective mean squared values ​​(RMS) were obtained in the 60-180Hz and 180-260Hz frequency ranges in the X / Y / Z directions. These three directions cover the various dimensions of vibration that may occur at the wheel center, while the two selected frequency ranges cover the key frequency bands for tire structural sound transmission to the vehicle interior, causing noise. By analyzing the RMS values ​​within these specific frequency ranges, the noise level transmitted from the wheel center vibration to the vehicle interior can be intuitively and quantitatively assessed.

[0033] Tire noise collection and analysis:

[0034] On a high-speed uniformity test bench, data were collected on the tire as its speed decreased from 80 km / h to 40 km / h using a tracking speed sampling method.

[0035] The sampled signals are subjected to Fourier transform and averaging to reduce random noise interference and improve the stability and reliability of the data.

[0036] like Figure 1 As shown, the effective values ​​(RMS) in the frequency ranges of 60-180Hz and 180-260Hz in the X / Y / Z directions were obtained to evaluate the vibration level at the wheel center.

[0037] Data example:

[0038]

[0039] Construction of the decibel calculation model:

[0040] Let the time functions of the forces in the three directions at the wheel center obtained from the tire bench test be Fx(t), Fy(t), and Fz(t).

[0041] Performing a Fourier transform on the time functions of the forces in these three directions yields their expressions in the frequency domain, namely Fx(ω), Fy(ω), and Fz(ω), where ω is the angular frequency.

[0042] Based on the vehicle's structural dynamics characteristics, a transfer function matrix [H(ω)] is established for the noise transfer from the wheel center to the vehicle interior. The transfer function matrix [H(ω)] is the ratio of the noise interior matrix to the acceleration matrix at the wheel center. The noise interior matrix is ​​obtained by Fourier transforming the measured sound pressure and time matrices. The noise interior matrix and the acceleration matrix at the wheel center are acquired using a HeadLab 36 or LabV36 II testing instrument. The noise interior transfer function matrix describes how the force at the wheel center is transmitted through the vehicle structure and converted into noise. The key is to obtain the vehicle's structural dynamics characteristics through methods such as TPA (Transmission Path Analysis) experiments or finite element analysis to determine the transfer function matrix [H(ω)]. This may require specialized testing equipment and analysis software.

[0043] The sound pressure frequency domain function P(ω) of the in-vehicle noise can be calculated using the following formula:

[0044]

[0045] The sound pressure frequency domain function P(ω) is subjected to inverse Fourier transform to obtain the sound pressure time function P(t).

[0046] Calculate the effective value (RMS) of the sound pressure time function P(t), and calculate the decibel value of the in-vehicle noise according to the sound pressure level formula.

[0047]

[0048] in For reference sound pressure level.

[0049] However, the above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A method for calculating the decibel level of tire structural noise, characterized in that, Includes the following steps: S10: The tire is decelerated from a high-speed rotation state to a low-speed rotation state, and vibration signals are collected during the deceleration process; S20: Preprocess the vibration signal to obtain the frequency domain signal; S30: Obtain the effective value of the frequency domain signal located at the mid-to-low frequency on the X-axis, Y-axis, and Z-axis; S40: Establish a decibel calculation model based on the effective value of the frequency domain signal.

2. The method for calculating the decibel level of tire structural noise according to claim 1, characterized in that, The steps for uniformly reducing the tire's rotation speed from high speed to low speed and collecting vibration signals during the deceleration process are as follows: The tire was mounted on a high-speed uniformity test bench, and the tire speed was uniformly reduced from 80 km / h to 40 km / h. The vibration signal of the tire was collected using the tracking speed method.

3. The method for calculating the decibel level of tire structural noise according to claim 1, characterized in that, The steps for preprocessing vibration signals to obtain frequency domain signals are as follows: The vibration signal is converted into a frequency domain signal by performing a Fourier transform and then averaging.

4. The method for calculating the decibel level of tire structural noise according to claim 1, characterized in that, The steps to obtain the effective values ​​of the frequency domain signal located in the mid-to-low frequency range on the X, Y, and Z axes are as follows: Obtain the effective values ​​in the frequency ranges of 60-180Hz and 180-260Hz in the X / Y / Z directions, and analyze the effective values.

5. The method for calculating the decibel level of tire structural noise according to claim 1, characterized in that, The steps to establish a decibel calculation model based on the effective value of the frequency domain signal are as follows: Let the time functions of the forces in the X, Y, and Z directions at the wheel center obtained from the tire bench test be Fx(t), Fy(t), and Fz(t), respectively. Performing Fourier transforms on the time functions of the forces in the X, Y, and Z directions yields their expressions in the frequency domain, namely Fx(ω), Fy(ω), and Fz(ω), where ω is the angular frequency; Based on the structural dynamics characteristics of the vehicle, the transfer function matrix [H(ω)] from the wheel center to the vehicle interior noise is established; The sound pressure frequency domain function P(ω) of the in-vehicle noise can be calculated using the following formula: ； The inverse Fourier transform of the sound pressure frequency domain function P(ω) yields the sound pressure time function P(t); Calculate the effective value of the sound pressure time function P(t), and calculate the decibel value of the in-vehicle noise using the sound pressure level formula. , ； in For reference sound pressure level.

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