Supporting performance of magnetic-liquid double suspension bearing under wear of magnetic poles

As a new type of suspension bearing, magnetic-liquid double suspension bearing (MLDSB) is mainly supported by electromagnetic suspension and supplemented by hydrostatic supporting. Its supporting capacity and stiffness can be greatly improved, and then it is suitable for the occa-sions of medium speed, heavy load. Due to the small liquid film thickness (It is smaller nearly 10 times than air-gap), the eccentricity, crack, bending of the rotor, the assembly error, it is easy to cause clearance-rubbing fault between the rotor and stator. The coating can be worn and peeled, the operating stability can be reduced, and then it is one of the key problems of restricting the development and application of MLDSB. Therefore, a new method for soft measurement of wear of magnetic pole is presented, and the expressions of bearing stiffness and damping in the magnetic pole coating-wear mode and the dynamic equation of two DOF rubbing system are established. The influence of wear amount on the supporting performance and dynamic behavior under dif-ferent wear conditions is simulated numerically, and the supporting performance is restored by adjusting the electromagnetic control parameters. The study shows that supporting performance and operation stability of bearing system are reduced due to wear of the magnetic poles, and wear of y-direction is the most serious, bifurcation and chaos occur in the system, and secondary wear occurs between the magnetic pole and flux sleeve. By measuring the pressure and flow rate of the static pressure system in real time, the wear amount of each magnetic pole coating can be predicted effectively, which provides a theoretical basis for the safe and stable operation of MLDSB. According to the wear value of each magnetic pole coating, the control parameters of the electromagnetic system are adjusted to make the supporting performance of the MLDSB return to the initial theoretical state to prevent secondary wear. The research can provide a theoretical basis for the safe and stable operation of MLDSB.