Method for testing noise and vibration of refrigeration fan of refrigerator

Abstract

The invention provides a method for testing noise and vibration of a refrigeration fan of a refrigerator, relates to the field of vibration testing of refrigerators, and aims to solve the problem that the real noise performance of the fan in a complex environment in the refrigerator cannot be reflected in the current noise testing of the fan of the air-cooled refrigerator. The actual installation states of a fan, an air duct and a box body are reserved to eliminate single body test deviation, vibration and noise data are synchronously collected, time domain and frequency domain analysis is covered, vibration-noise causal relation tracing is achieved, the coupling frequency band and energy distribution of vibration and noise are quantified through time domain and frequency domain conjoint analysis, and therefore the noise source and the coupling frequency band are positioned, and the noise quality is improved. And targeted optimization is facilitated, and the noise optimization efficiency and the optimized noise control effect are improved.

Description

Technical Field

[0001] The present invention relates to the field of refrigerator vibration testing, and in particular to a method for testing noise and vibration of a refrigerator refrigeration fan. Background Art

[0002] In air-cooled refrigerators, the internal refrigeration fan is the main source of refrigerator noise. During the research and development process, it is necessary to accurately identify the sound and vibration characteristics of the fan in order to optimize the refrigerator noise.

[0003] Current methods for identifying fan noise and vibration primarily rely on testing and analyzing the fan itself. However, testing only the fan itself cannot represent the fan's noise performance in a refrigerator. Alternatively, the air duct and fan are tested separately, collecting only noise or vibration data. Some current noise monitoring methods are used for threshold monitoring, and the collected data is not analyzed. Some refrigerator duct vibration testing methods, while testing both with the refrigerator in place and with the fan duct removed, still only collect vibration data. This approach of performing vibration testing with the fan duct removed is inconsistent with actual usage scenarios. In the actual operation of air-cooled refrigerators, fan vibration also affects noise. Collecting only noise or vibration data results in inadequate identification of fan noise problem areas, making noise optimization inconvenient. Summary of the Invention

[0004] The purpose of the present invention is to address the defects of the prior art and provide a refrigerator refrigeration fan noise and vibration testing method. The test is conducted in the environment of the entire refrigerator, retaining the actual installation status of the fan, air duct and cabinet to eliminate single-unit test deviations, synchronously collecting vibration and noise data, covering time domain and frequency domain analysis, and realizing vibration-noise causal relationship tracing. Through joint analysis of time and frequency domains, the coupling frequency band and energy distribution of vibration and noise are quantified, thereby locating the noise root source and coupling frequency band, facilitating targeted optimization, and improving noise optimization efficiency and optimized noise control effect.

[0005] In order to solve the above problems, the following solutions are adopted:

[0006] A method for testing noise and vibration of a refrigerator refrigeration fan, comprising:

[0007] A triaxial acceleration sensor is placed on the air duct panel of the refrigerator's internal fan, and a microphone is placed outside the refrigerator to simultaneously collect fan vibration information and noise information outside the refrigerator;

[0008] Perform time-domain analysis on fan vibration and noise information to obtain the temporal relationship between vibration acceleration and noise sound pressure level, and identify the time period when vibration excites noise.

[0009] Perform frequency domain analysis on the period of vibration-excited noise to obtain the overlapping area of ​​the vibration main frequency and the noise main frequency, and determine the coupling frequency band of the vibration main frequency and the noise main frequency;

[0010] According to the coupling frequency band, the internal structure of the refrigerator is adjusted to reduce the refrigerator noise.

[0011] Furthermore, when collecting the vibration information and noise information of the fan, the power supply of the refrigerator compressor is disconnected and the fan is operated alone.

[0012] Furthermore, the microphone is located in the horizontal extension direction of the air duct outlet, and a windproof ball is provided on the side of the microphone facing the air duct.

[0013] Furthermore, the time domain analysis of the wind turbine vibration information and noise information includes:

[0014] Compare the waveforms of fan vibration information and noise information, and calculate the mutual correlation coefficient.

[0015] Furthermore, the time period for identifying vibration-excited noise is a time period for identifying synchronous mutations of the vibration acceleration peak value and the noise sound pressure level peak value.

[0016] Furthermore, the coupling frequency band of the vibration main frequency and the noise main frequency is determined by FFT spectrum and coherence function.

[0017] Furthermore, the FFT transformation is performed on the time period of vibration-excited noise to generate a spectrum diagram, analyze the main frequency distribution of the fan vibration information and noise information, and identify the overlapping area of ​​the vibration acceleration peak frequency and the noise sound pressure level peak frequency.

[0018] Furthermore, the coherence function is used to calculate the coherence value of the overlapping area frequency. If the coherence value is greater than the set value, it is determined that the frequency is the coupling frequency band of the vibration main frequency and the noise main frequency, and the noise information of this frequency is affected by the resonance of the fan structure; otherwise, it is determined that the noise information of this frequency is affected by the airflow noise.

[0019] Furthermore, adjusting the internal structure of the refrigerator based on the coupling frequency band includes: adjusting the mechanical structure, airflow characteristics and / or acoustic environment, blocking or weakening the transmission path of vibration energy to noise, or reducing the energy amplitude of the coupling frequency band.

[0020] Furthermore, the adjustment of the mechanical structure includes adjusting the air duct stiffness and the dynamic balance of the fan impeller, adjusting the airflow characteristics includes adjusting the airflow field shape in the air duct, reducing turbulence intensity and pressure pulsation, and adjusting the acoustic environment includes increasing sound-absorbing materials to absorb or dissipate noise energy.

[0021] Compared with the prior art, the present invention has the following advantages and positive effects:

[0022] To address the problem that the current noise test of air-cooled refrigerator fans cannot reflect the actual noise performance of the fan in the complex environment inside the refrigerator, the test is conducted in the environment of the entire refrigerator, retaining the actual installation status of the fan, air duct, and cabinet to eliminate single-unit test deviations, synchronously collecting vibration and noise data, covering time domain and frequency domain analysis, and realizing vibration-noise causal relationship tracing. Through joint analysis of time and frequency domains, the coupling frequency band and energy distribution of vibration and noise are quantified, thereby locating the root cause of noise and the coupling frequency band, facilitating targeted optimization, improving noise optimization efficiency and optimized noise control effect.

[0023] A triaxial acceleration sensor is placed on the surface of the fan duct panel inside the refrigerator to collect XYZ vibration data and capture the coupled vibration characteristics of the fan and the duct. A microphone is placed outside the refrigerator in the direction of the fan axial outlet to collect noise data. A wind shield is used to avoid interference from environmental noise to ensure that the sound pressure level data is true and valid. The compressor power supply is disconnected and only the fan is running to eliminate interference from other sound sources, focusing on acoustic and vibration analysis under independent fan working conditions.

[0024] Targeted optimization is performed based on coupling characteristics, adjusting the mechanical structure, airflow characteristics, or acoustic environment as needed. For frequency bands dominated by mechanical vibration, the dynamic balance of the fan impeller is optimized to reduce the vibration amplitude of rotational excitation. Elastic supports (such as rubber vibration damping pads) are installed between the fan and the duct to block the vibration transmission path. For frequency bands dominated by airflow noise, the duct flow field design is improved (such as expanding the inlet cross-sectional area and installing guide vanes) to reduce turbulence intensity. Sound-absorbing materials (such as glass wool) are laid on the inner wall of the duct to dissipate high-frequency noise energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 Schematic diagram of the arrangement of information collection components in the noise and vibration testing method for a refrigerator refrigeration fan in Example 1 of the present invention.

[0027] In the figure, 1. Refrigerator; 2. Three-axis acceleration sensor; 3. Microphone; 4. Fan. DETAILED DESCRIPTION

[0028] Example 1

[0029] In a typical embodiment of the present invention, Figure 1 As shown in the figure, a noise and vibration test method for a refrigerator refrigeration fan is given.

[0030] The traditional method tests the fan body or the air duct + fan separately from the refrigerator body, which cannot reflect the actual noise performance of the fan in the complex environment inside the refrigerator (such as temperature changes affecting the air duct mode and the coupling of the box structure). When collecting data, only noise data is collected, and the impact of vibration on noise cannot be correlated; only vibration data is collected, and the lack of noise data support makes it impossible to fully analyze the acoustic-vibration coupling mechanism. Based on this, this embodiment provides a noise and vibration test method for refrigerator refrigeration fans, which is tested in the environment of the entire refrigerator, retaining the actual installation status of the fan, air duct and refrigerator body, and synchronously collecting vibration and noise data, covering time domain and frequency domain analysis, so as to locate the source of noise and the coupling frequency band, facilitate targeted optimization, and improve the noise optimization efficiency and the noise control effect after optimization.

[0031] like Figure 1 As shown, the refrigerator refrigeration fan noise and vibration test method includes the following steps:

[0032] A triaxial acceleration sensor is placed on the air duct panel of the refrigerator's internal fan, and a microphone is placed outside the refrigerator to simultaneously collect fan vibration information and noise information outside the refrigerator;

[0033] Perform time-domain analysis on fan vibration and noise information to obtain the temporal relationship between vibration acceleration and noise sound pressure level, and identify the time period when vibration excites noise.

[0034] Perform frequency domain analysis on the period of vibration-excited noise to obtain the overlapping area of ​​the vibration main frequency and the noise main frequency, and determine the coupling frequency band of the vibration main frequency and the noise main frequency;

[0035] According to the coupling frequency band, the internal structure of the refrigerator is adjusted to reduce the refrigerator noise.

[0036] Among them, Figure 1 As shown, a triaxial accelerometer is installed on the surface of the refrigerator's internal fan duct panel, collecting X, Y, and Z vibration data to capture the coupled vibration characteristics of the fan and duct, such as the resonance direction. The microphone is positioned horizontally along the duct outlet to maximize the detection of fan noise, ensuring accurate noise collection. Furthermore, a wind shield is installed on the side of the microphone facing the duct. This shield effectively reduces interference from ambient wind on the microphone's collected data, preventing measurement errors caused by wind noise and ensuring that the collected noise information truly reflects the noise generated by the fan.

[0037] When collecting fan vibration and noise information, disconnect the refrigerator compressor power supply, run the fan alone, and eliminate interference from other sound sources. This allows the test data to more accurately reflect the vibration and noise characteristics of the fan itself, meeting the acoustic and vibration analysis requirements under independent fan operating conditions.

[0038] When performing time-domain analysis of wind turbine vibration and noise information, the cross-correlation coefficient is calculated by comparing the waveforms of the two. Waveform comparison allows for intuitive observation of the temporal trends of vibration and noise, while the cross-correlation coefficient quantitatively describes the degree of correlation between the two. The closer the cross-correlation coefficient is to 1, the stronger the correlation between vibration and noise, indicating a greater impact of vibration on noise.

[0039] Identifying vibration-induced noise periods involves identifying when the vibration acceleration peak and the noise sound pressure level peak experience a sudden change. During refrigerator fan operation, if a vibration acceleration peak is accompanied by a sudden change in the noise sound pressure level, this period is likely a critical period for vibration-induced noise. Accurately identifying these periods allows us to identify the target range for subsequent frequency domain analysis.

[0040] The coupled frequency bands of the primary vibration and noise frequencies are determined using the FFT spectrum and coherence function. Specifically, an FFT (Fast Fourier Transform) is performed on the time period during which vibration excites noise to generate a spectrum. The FFT transform converts time-domain signals into frequency-domain signals. By analyzing the spectrum, we can clearly understand the energy distribution of the fan's vibration and noise information at different frequencies, thereby identifying the peak frequency of the fan's vibration acceleration and the peak frequency of the noise sound pressure level, and determining the primary vibration and noise frequencies.

[0041] The overlapping region between the primary vibration and noise frequencies is analyzed, and the frequency coherence value of the overlapping region is calculated using a coherence function. If the coherence value is greater than a set value, the frequency is determined to be a coupled frequency band between the primary vibration and noise frequencies, and the noise information at this frequency is affected by the fan's structural resonance. Conversely, the noise information at this frequency is determined to be affected by airflow noise. The coherence function is an important tool for measuring the correlation between two signals at different frequencies. When the frequency coherence value of the overlapping region is greater than a set value, it indicates a strong coupling relationship between vibration and noise at this frequency, and this frequency is a coupled frequency band that requires special attention.

[0042] According to the determined coupling frequency band, the internal structure of the refrigerator is adjusted, specifically by adjusting the mechanical structure, airflow characteristics and acoustic environment.

[0043] Mechanical structural adjustments involve adjusting the duct stiffness and dynamic balancing of the fan impeller. Insufficient duct stiffness can cause the duct to resonate under the influence of fan vibration, amplifying noise. Poor impeller dynamic balancing can generate unbalanced forces during fan operation, causing vibration and noise. By optimizing duct stiffness and adjusting impeller dynamic balancing, vibration and noise caused by mechanical structural issues can be reduced, blocking or weakening the path through which vibration energy is transferred to noise.

[0044] To adjust airflow characteristics, the flow field within the duct is adjusted to reduce turbulence intensity and pressure pulsation. Turbulence and pressure pulsation are a major cause of noise generated by fan operation. By optimizing the duct design, such as changing the duct shape and adding guide devices, the flow field can be improved, turbulence intensity and pressure pulsation can be reduced, thereby reducing noise generation.

[0045] To adjust the acoustic environment, add sound-absorbing materials to absorb or dissipate noise energy. Adding sound-absorbing materials, such as sound-absorbing cotton, to appropriate locations inside the refrigerator can absorb the noise generated by the fan, converting the noise energy into other forms of energy (such as heat) and dissipating it, thereby reducing the propagation and radiation of noise inside the refrigerator.

[0046] In this embodiment, the test is carried out in the environment of the entire refrigerator, retaining the actual installation status of the fan, air duct, and cabinet, which can truly reflect the vibration and noise conditions of the fan during actual use. Compared with single-unit testing, the test deviation is greatly reduced, providing reliable data support for subsequent analysis and optimization.

[0047] By synchronously collecting vibration and noise data and conducting joint analysis in the time and frequency domains, we can clearly trace the causal relationship between vibration and noise, accurately locate the root cause of noise and the coupled frequency band, changing the previous limitation of analyzing noise problems from only a single perspective and providing a more accurate direction for noise optimization.

[0048] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for testing noise and vibration of a refrigerator refrigeration fan, characterized in that: include: A triaxial acceleration sensor is placed on the air duct panel of the refrigerator's internal fan, and a microphone is placed outside the refrigerator to simultaneously collect fan vibration information and noise information outside the refrigerator; Perform time-domain analysis on fan vibration and noise information to obtain the temporal relationship between vibration acceleration and noise sound pressure level, and identify the time period when vibration excites noise. Perform frequency domain analysis on the period of vibration-excited noise to obtain the overlapping area of ​​the vibration main frequency and the noise main frequency, and determine the coupling frequency band of the vibration main frequency and the noise main frequency; According to the coupling frequency band, the internal structure of the refrigerator is adjusted to reduce the refrigerator noise.

2. The refrigerator refrigeration fan noise and vibration testing method according to claim 1, wherein: When collecting fan vibration and noise information, disconnect the power supply to the refrigerator compressor and operate the fan alone.

3. The refrigerator refrigeration fan noise and vibration testing method according to claim 1 or 2, characterized in that: The microphone is located in the horizontal extension direction of the air duct outlet, and a windproof ball is provided on the side of the microphone facing the air duct.

4. The refrigerator refrigeration fan noise and vibration testing method according to claim 1, wherein: The time domain analysis of the fan vibration information and noise information includes: Compare the waveforms of fan vibration information and noise information, and calculate the mutual correlation coefficient.

5. The refrigerator refrigeration fan noise and vibration testing method according to claim 4, characterized in that: The time period for identifying vibration-excited noise is a time period for identifying synchronous mutations of the vibration acceleration peak value and the noise sound pressure level peak value.

6. The refrigerator refrigeration fan noise and vibration testing method according to claim 1, wherein: The coupling frequency band of the main vibration frequency and the main noise frequency is determined by FFT spectrum and coherence function.

7. The refrigerator refrigeration fan noise and vibration testing method according to claim 6, characterized in that: Perform FFT transformation on the period of vibration-excited noise to generate a spectrum diagram, analyze the main frequency distribution of fan vibration information and noise information, and identify the overlapping area of ​​the peak frequency of vibration acceleration and the peak frequency of noise sound pressure level.

8. The refrigerator refrigeration fan noise and vibration testing method according to claim 6 or 7, characterized in that: The coherence function is used to calculate the coherence value of the overlapping area frequency. If the coherence value is greater than the set value, the frequency is determined to be the coupling frequency band of the vibration main frequency and the noise main frequency, and the noise information of this frequency is affected by the resonance of the fan structure; otherwise, the noise information of this frequency is determined to be affected by the airflow noise.

9. The refrigerator refrigeration fan noise and vibration testing method according to claim 1, wherein: Adjusting the internal structure of the refrigerator based on the coupling frequency band includes: adjusting the mechanical structure, airflow characteristics and / or acoustic environment, blocking or weakening the transmission path of vibration energy to noise, or reducing the energy amplitude of the coupling frequency band.

10. The refrigerator refrigeration fan noise and vibration testing method according to claim 9, characterized in that: The adjustment of the mechanical structure includes adjusting the air duct stiffness and the dynamic balance of the fan impeller, adjusting the airflow characteristics includes adjusting the airflow field shape in the air duct, reducing turbulence intensity and pressure pulsation, and adjusting the acoustic environment includes increasing sound-absorbing materials to absorb or dissipate noise energy.

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