Analysis and experimental study of vibration and noise of double disk magnetic coupler

In order to analyze and optimize the characteristics of vibration and noise in the process of double disk mag- netic coupler design,the method to analyze the vibration and noise with modal superposition is proposed. The double- disk magnetic coupler has the advantages of high torque density and high efficiency,hence,it has gradually become a flexible transmission device in coal mine machinery. Due to the non-sinusoidal distribution of the rotor magnetic field and eddy current harmonics in the double-disk magnetic coupling system,there are inevitable fluctuations in the output torque of the double-disk magnetic coupler. According to these characteristics of the coupler,the optimal combination of the parameters of low vibration and noise can reduce the electromagnetic vibration and noise in practice,which is helpful in reducing the manufacturing cost. Therefore,it is very important to predict and calculate the characteristics of electromagnetic vibration and noise accurately at the design stage of the double- disk magnetic coupler for reducing cost and improving its operation stability. The modal superposition response method was proposed to calculate electro- magnetic vibration noise based on the structural characteristics of the double-disk magnetic coupler in this paper. The analytical model of the electromagnetic radial force was established,and the harmonic response of the main electromag- netic radial force wave in the working frequency was analyzed under the coupling action of multiple physical fields. Al- so,an experimental verification was conducted on a double-disk magnetic coupler test bench with a rated power of 55 kW. Based on the Maxwell tensor method,an analytical model of the radial electromagnetic force of the double-disk magnetic coupler was established. It was concluded that the main cause of vibration and noise is the electromagnetic radial force wave of orders 0 and 10. The NVH characteristic of harmonic response was analyzed by means of multi- physical field-coupling analysis. The results show that the vibration acceleration and deformation of the 0-order force wave are greater than that of the 10-order force wave. Thus,the electromagnetic vibration of the double-disk magnetic coupler is primarily attributed to the 0-order force wave. Vibration tests were conducted on a double-disk magnetic coupler test bench with a rated power of 55 kW and maximum speed of 1 500 r / min. The experimental results show that the maximum vibration peaks and frequencies are about 35 m / s2 and 4 950 Hz at 1 500 r / min,and the errors cor- responding to the finite element simulation results are 6. 3% and 1. 1% . When the input speed of the variable frequen- cy motor increases in turn,the theoretical value and simulation value of the vibration acceleration are close to the curve shape of the test value,and the error is small. The maximum error between the noise estimation and the measured value is only 8. 9% ,which basically verifies the correctness of the modal superposition method proposed in this paper.