Rapid detection method and system for improving tire cavity noise effect through mute cotton

Abstract

The invention relates to the technical field of tire NVH testing, in particular to a rapid detection method and system for improving the tire cavity noise effect through mute cotton. According to the method, only two tires (which are pasted with mute cotton and not pasted with mute cotton) are needed, the tires are installed on a vehicle rim and hung on a rigid support, accelerometers are arranged in the center of the rim and the center of a tread, a force hammer is used for conducting radial excitation on the center of the rim, a frequency response function is obtained, and force transmission FT is calculated. The improvement effect of the mute cotton on the cavity noise is quantified by extracting a force transmission peak difference value (CT = FTPeak-2-FTPeak1) within the frequency band of 180-250 Hz. According to the method, real vehicle assembly or a professional test field is not needed, detection can be completed in a laboratory environment quickly, simply and conveniently at low cost, the verification period is remarkably shortened, and objective and comparable noise reduction evaluation indexes are provided.

Description

Technical Field

[0001] The present invention relates to the technical field of tire NVH testing, and particularly to a rapid detection method and system for improving the cavity noise effect of a tire by a sound-absorbing cotton. Background Art

[0002] With the continuous improvement of consumers' requirements for the quiet and comfortable performance of automobiles, especially under the promotion of the rapid development of the new energy vehicle market, how to further reduce the noise during vehicle driving has become one of the key issues in the automotive industry. Among them, as the only component in contact with the road surface of the vehicle, the noise level of the tire has an important impact on the NVH (noise, vibration, and harshness) performance of the whole vehicle. Traditional noise reduction methods mainly focus on optimizing the tire tread design, tread formula, or carcass structure in order to achieve a relatively significant noise reduction effect in the high-frequency band. However, in actual use, the cavity resonance noise in the mid-low frequency band often becomes one of the main sources of vehicle noise, and traditional high-frequency noise suppression technologies are difficult to effectively improve this problem.

[0003] In recent years, a technical solution of pasting noise reduction materials (usually referred to as "sound-absorbing cotton" or "noise reduction sponge") on the inner wall of the tire has gradually emerged in the industry, which can quickly reduce the in-vehicle noise without significantly changing the formula and structure of the tire itself. Actual vehicle installation tests and professional test instruments also confirm that the tires pasted with sound-absorbing cotton have an obvious effect on reducing cavity noise.

[0004] However, it is time-consuming and laborious to verify the effect of the sound-absorbing cotton on improving the cavity noise of the tire. Currently, the in-vehicle method is mainly adopted, that is, two sets of test tires are prepared, one set of 4 tires is pasted with sound-absorbing cotton, and the other set of 4 tires is not pasted with sound-absorbing cotton. They are respectively installed on the adapted test vehicles, and the sound pressure level values of the in-vehicle noise are collected on the road surface of a professional test site to compare the improvement effect of the cavity noise of the sound-absorbing cotton pasting scheme relative to the non-sound-absorbing cotton pasting scheme. This verification method requires at least 8 tires, which need to be installed on the test vehicles, and also needs to be verified in a professional test field. The verification cycle is long and the verification cost is high, which is not conducive to quickly comparing the effect of the sound-absorbing cotton on improving the cavity noise of the tire.

[0005] However, due to the need for real vehicles, professional test sites, and a large number of test tires for the test of cavity noise, the existing in-vehicle method verification mode has a high cost, a long cycle, and requires multiple tires pasted with sound-absorbing cotton and non-pasted sound-absorbing cotton to be prepared at the same time for comparative evaluation. This test method poses a great challenge to the R & D cost and test cycle of enterprises, and is also not conducive to quickly screening and verifying different noise reduction schemes in the early stage of product development. Therefore, how to quickly detect the improvement effect of the sound-absorbing cotton on the cavity noise of the tire in a relatively simple manner under laboratory conditions has become a technical problem to be solved urgently in this field. Summary of the Invention

[0006] To solve the above technical problems, the objective of the present invention is to provide a rapid detection method for the effect of sound-absorbing cotton in improving tire cavity noise. This method involves preparing 2 test tires, with sound-absorbing cotton pasted on one tire and not on the other. The acceleration frequency response functions at the tire tread and the rim center are respectively measured, the radial force transmission is calculated, and the peak difference within 180 - 250 Hz of the radial force transmission is taken as the index for evaluating the effect of sound-absorbing cotton in improving tire cavity noise.

[0007] To achieve the above objective, the present invention adopts the following technical solutions: A rapid detection method for the effect of sound-absorbing cotton in improving tire cavity noise, the method comprising the following steps: 1) Install a tire with sound-absorbing cotton pasted thereon on a vehicle rim and adjust the tire inflation pressure; 2) Suspend the tire with the sound-absorbing cotton pasted thereon on a rigid support by an elastic rope; 3) Arrange an accelerometer at the center of the vehicle rim and at the center of the tire tread respectively; 4) Use a force hammer to strike the center of the rim to obtain data for radial force transmission testing; 5) Let the frequency response function measured at the rim center be FRF center , and the frequency response function measured at the tread be FRF tread , then the force transmission is FT = FRF tread / FRF center ; 6) Plot or obtain the force transmission curve FT with dB as the ordinate unit and Hz as the abscissa unit; 7) Calculate the peak value of the force transmission curve FT within the range of 180 - 250 Hz, denoted as FT Peak1 ; 8) For another tire without sound-absorbing cotton pasted thereon, calculate the peak value FT within the range of 180 - 250 Hz according to steps 1) to 7); Peak2 ; 9) Characterize the effect of sound-absorbing cotton in improving tire cavity noise through CT = FT Peak2 - FT Peak1 , where the larger the CT value, the more significant the noise reduction effect of the sound-absorbing cotton.

[0008] Preferably, the tire inflation pressure range in step 1) is 180 kPa - 350 kPa and is appropriately adjusted according to the tire specifications.

[0009] Preferably, the suspension position of the elastic rope in step 2) is set at the top of the rigid support, so that the tire is as far away from the ground and other interference sources as possible during the test.

[0010] Preferably, the position for arranging the accelerometer in step 3) is at the axial center of the tire and the rim to reduce the influence of the tire's own gravity on the test results.

[0011] Preferably, when using the force hammer to strike in step 4), the striking position of the force hammer is the same as or adjacent to the installation position of the accelerometer at the rim center to ensure the accuracy and consistency of the test.

[0012] Preferably, in step 7), the frequency range of 180 - 250 Hz can be appropriately adjusted upward or downward according to the cavity resonance characteristics of different tire specifications to cover the main frequency band of the tire cavity noise.

[0013] Furthermore, the present invention also provides a detection system for implementing the method, and the system includes: A rigid bracket for providing a support and suspension space during the test; An elastic suspension member for suspending the tire on the rigid bracket; At least two accelerometers respectively for being installed at the rim center and the tread center; A force hammer for applying a striking force to the rim center; A data acquisition and processing unit connected to the accelerometer for acquiring and recording frequency response function data and calculating the force transfer FT and CT values according to FRF center and FRF tread and calculating the force transfer FT and CT values.

[0014] Preferably, the data acquisition and processing unit includes a signal acquisition module and a data analysis module. The signal acquisition module acquires the time-domain signal output by the accelerometer and converts it into a frequency-domain signal, and the data analysis module calculates the frequency-domain signal to obtain the FT and CT values.

[0015] Preferably, the elastic suspension member is several elastic ropes or elastic bands capable of bearing the corresponding weight, and its length and elastic coefficient can be correspondingly set according to the tire shape size and weight.

[0016] Preferably, the accelerometer is detachably or fixedly installed at the designated positions of the rim and the tread by means of magnetic adsorption, bolts or strong adhesive tapes, etc., so as to facilitate quick replacement or movement after the test.

[0017] Due to adopting the above technical solution, compared with the prior art, the present invention adopts a radial force transfer test method in a laboratory environment to quickly evaluate the improvement effect of the sound-absorbing cotton on the tire cavity noise, and has the following beneficial effects: 1. Short test cycle and low cost: The present invention only requires two tires (one with sound-absorbing cotton pasted and the other without) to be prepared, and there is no need to actually install the tires on a vehicle or verify them at a professional test site, significantly shortening the verification cycle and greatly reducing the test cost; 2. Simple and reliable detection method: By measuring the acceleration frequency response functions of the rim center and the tread center and calculating the radial force transmission, and then extracting the peak values within the target frequency band (180 - 250 Hz) for comparison, the noise reduction effect difference of the sound-absorbing cotton can be obtained, with simple operation and easy implementation; 3. Intuitive result evaluation: Using the peak difference CT as a quantitative index, the improvement amplitude of the sound-absorbing cotton in cavity noise can be visually judged, providing a unified and comparable evaluation standard for the optimization and screening of different noise reduction schemes; 4. Wide application range: It can quickly detect and compare different specifications of tires and different types of sound-absorbing cotton materials, providing a flexible experimental means for tire R & D and the application of noise reduction materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flowchart of the method of the present invention.

[0019] Figure 2 It is a comparison chart of the force transmission curves FT of the tire with sound-absorbing cotton and the tire without pasted sound-absorbing cotton. DETAILED DESCRIPTION OF THE INVENTION

[0020] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] As Figure 1 shown, a rapid detection method for the effect of sound-absorbing cotton in improving the cavity noise of tires, the method includes the following steps: 1. Tire preparation and installation Select a tire with a specification of 235 / 45 ZR18, and paste a sound-absorbing cotton material on its inner wall; install the tire with the pasted sound-absorbing cotton on a vehicle rim, and adjust the inflation pressure to 230 kPa; use an elastic rope to hang the rim together with the tire on a rigid bracket, so that the tire can freely hang and be far from the ground or other supports, ensuring the minimization of external interference during the test.

[0022] 2. Accelerometer arrangement Install an accelerometer at the center of the vehicle wheel rim (the optional position is near the inner axial center of the wheel rim), denoted as "rim accelerometer"; install another accelerometer at the center of the tire tread (the optional position is the center line position of the crown part), denoted as "tread accelerometer"; the accelerometer can be installed by means of magnetic adsorption, bolt fixation or strong tape, etc., to ensure its firmness and reliability during the measurement process.

[0023] 3. Radial force transfer test Use a force hammer to strike the center position of the wheel rim from the outside, and strike it multiple times within a short period (such as several seconds to more than ten seconds) to ensure the consistency and accuracy of the test data; at the same time, the data acquisition system records the acceleration time-domain signals of the rim accelerometer and the tread accelerometer; convert the acceleration time-domain signals into frequency-domain signals to obtain the frequency response functions at each frequency point. Among them: The frequency response function measured at the center of the wheel rim is defined as FRF center ; The frequency response function measured at the center of the tread is defined as FRF tread .

[0024] 4. Force transfer calculation and peak extraction The present invention defines the force transfer FT = FRF tread / FRF center ; Taking dB as the ordinate unit and Hz as the abscissa unit, plot or record the curve of the force transfer varying with frequency as the FT curve (as Figure 2 shown); within the target frequency band of 180 - 250 Hz, calculate and extract the peak value of the force transfer curve FT, denoted as FTPeak1.

[0025] 5. Control test Prepare another tire without pasting sound-absorbing cotton (with the same specifications as above), and conduct the test in the same manner according to the above steps 1) - 4); obtain the force transfer peak value FTPeak2 within the range of 180 - 250 Hz.

[0026] 6. Difference calculation and effect evaluation Obtain the effect index of the sound-absorbing cotton on improving the tire cavity noise through CT = FTPeak2 - FTPeak1; the larger the value of CT, the more obvious the improvement amplitude of the tire cavity noise after pasting the sound-absorbing cotton.

[0027] In this embodiment, taking the 235 / 45 ZR18 tire as an example, the specifically measured FTPeak1 and FTPeak2 are 5.4 dB and 23.4 dB respectively. Then CT = 23.4 - 5.4 = 18 dB. It can be seen that the sound insulation cotton can significantly reduce the tire cavity noise in this frequency band.

[0028] The above is the description of the embodiments of the present invention. Through the above description of the disclosed embodiments, those skilled in the art can implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel points disclosed herein.

Claims

1. A rapid detection method for improving tire cavity noise with mute cotton, characterized in that: The method comprises the following steps: 1) Install a tire with silent cotton on the rim of the vehicle and adjust the tire inflation pressure; 2) The tire with the sound-proof cotton is hung on a rigid bracket through an elastic rope; 3) Arranging an accelerometer at the center of the vehicle rim and at the center of the tire tread respectively; 4) Using a hammer to strike the center of the rim to obtain radial force transmission test data; 5) The frequency response function measured at the center of the rim is FRF center , the frequency response function measured at the tread is FRF tread , then the force transmission is FT = FRF tread / FRF center ; 6) Draw or obtain the force transfer curve FT with dB as the vertical coordinate unit and Hz as the horizontal coordinate unit; 7) Calculate the peak value of the force transfer curve FT in the range of 180 to 250 Hz, recorded as FT Peak1 8) For another tire without soundproofing cotton, calculate the peak FT in the range of 180-250Hz according to steps 1) to 7). Peak2 ; 9) Through CT=FT Peak2 -FT Peak1 Characterizes the effect of silent cotton in improving tire cavity noise, where the larger the CT value, the more significant the noise reduction effect of the silent cotton.

2. The rapid detection method according to claim 1, characterized in that: The inflation pressure of the tire in step 1) ranges from 180 kPa to 350 kPa and is appropriately adjusted according to the tire specifications.

3. The rapid detection method according to claim 1, characterized in that The hanging position of the elastic rope in step 2) is set on the top of the rigid support, so that the tire is as far away from the ground and other interference sources as possible during the test.

4. The rapid detection method according to claim 1, characterized in that: The position for arranging the accelerometer in the step 3) is at the axial center of the tire and the rim to reduce the influence of the tire's own gravity on the test results.

5. The rapid detection method according to claim 1, characterized in that: In the step 4), when the hammer is used for striking, the striking position of the hammer is the same as or adjacent to the installation position of the accelerometer at the center of the rim to ensure the accuracy and consistency of the test.

6. The rapid detection method according to claim 1, characterized in that: The frequency range of 180-250 Hz in step 7) can be appropriately adjusted upward or downward according to the cavity resonance characteristics of different tire specifications to cover the main frequency band of the tire cavity noise.

7. A detection system for implementing the method according to any one of claims 1 to 6, characterized in that: The system includes: Rigid bracket, used to provide support and hanging space during testing; an elastic suspension member for suspending the tire on the rigid support; At least two accelerometers, respectively mounted at the center of the rim and the center of the tread; A hammer is used to apply a striking force to the center of the rim; The data acquisition and processing unit is connected to the accelerometer and is used to obtain and record the frequency response function data and calculate the frequency response function data according to the FRF. center With FRF tread Calculate the force transfer FT and CT values.

8. The detection system according to claim 7, characterized in that: The data acquisition and processing unit includes a signal acquisition module and a data analysis module. The signal acquisition module acquires the time domain signal output by the accelerometer and converts it into a frequency domain signal. The data analysis module calculates the frequency domain signal to obtain FT and CT values.

9. The detection system according to claim 7, characterized in that: The elastic suspension components are a plurality of elastic ropes or elastic belts that can bear corresponding weights, and the length and elastic coefficient of the elastic ropes or elastic belts can be set accordingly according to the tire's external dimensions and weight.

10. The detection system according to claim 7, characterized in that: The accelerometer can be detachably or fixedly installed at a designated position of the rim and the tread by means of magnetic adsorption, bolts or strong adhesive tape, so as to facilitate rapid replacement or movement after the test is completed.

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