As cabinet air conditioner units have recently been developed and expanded from the commercial field to the domestic field, the development of high-efficiency compressors and the development of low-noise compressors have become increasingly important. In order to reduce the noise of the inverter-controlled scroll compressor, a high-efficiency internal permanent magnet synchronous motor is installed in the compressor, and research is focused on how to reduce the noise and vibration below at high speed. It has been found through experiments that the noise reduction can not be achieved by adding a sound insulating cover in the following frequency bands. Now, we have found that the noise source in this band comes from the vibration of the crankshaft. This article will explain the causes of crankshaft vibration and the detailed improvement of vibration reduction.
The characteristics of high efficiency scroll compressors are being studied for cross-section of high efficiency scroll compressors for noise reduction. The reason for the high efficiency of such compressors is that in addition to being used as a drive motor, an improved high-voltage frame (motor: high-voltage side; rear scroll stator: low-pressure side) is also used. The flow of refrigerant gas and lubricating oil inside the compressor. The gas compressed by the vortex rotation enters the space below the motor through the inside of the crankshaft, and after the motor is effectively cooled, the gas is discharged to the outside. This type of refrigerant gas flow can effectively reduce the problem of suction overheating faced by ordinary models and improve the efficiency of the compressor. The noise source map is determined to represent the analysis result of the compressor noise octave. The working condition is (the following working conditions are the same). As can be seen from the figure, there is a sound level peak in the band, we will focus on this band and perform the following analysis. . Firstly, by measuring the surface deflection of a compressor under operating conditions, a continuous modal analysis is completed. It is found that in the band, the compressor vibrates integrally in the rigid body mode without deformation, and the lower part of the compressor is in an elliptical orbit. vibration. Second, to complete the crankshaft modal analysis, as shown in the figure, under actual working conditions, the crankshaft is assembled into the compressor during test installation. The response of the directly excited crankshaft at each point is measured using a laser vibrometer. Based on the frequency response function obtained in the test, through the modal analysis, it was found that the first deformation mode is an arc as shown in the figure, and there are frequencies in the axial direction and frequencies in the axial direction. In summary, the noise peak in the band is generated by the vibration of the lower part of the compressor in the rigid body mode, which is caused by the resonance of the first deformation mode of the crankshaft.
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