Hydrodynamic Bearing Structural Design of Blood Pump Based on Axial Passive Suspension Stability Analysis of Magnetic–Hydrodynamic Hybrid Suspension System

Abstract

Rotor suspension stability is one of the important performance indexes of a blood pump and the basis of determining whether the blood pump can be used in a clinic. Compared with the traditional magnetic suspension system, a single-winding, bearingless motor has the advantages of a compact structure, simple control system and low power consumption. In this pursuit, the present study aimed to envisage and design the magnetic suspension system coupled with a single-winding bearingless motor and permanent magnet bearings, establish the theoretical models of axial force and electromagnetic torque, and calculate the stiffness of the magnetic suspension system at the equilibrium point. Addressing the problem of the negative axial stiffness of the magnetic suspension system being negative, which leads to the instability of the suspension rotor, the hydrodynamic bearing structure was proposed and designed, and the critical stiffness to realize the stable suspension of the rotor was obtained based on the stability criterion of the rotor dynamics model. The optimal structural parameters of the hydrodynamic bearing are selected by integrating various factors based on the solution of the Reynolds equation and a stiffness analysis. Furthermore, the vibration experiment results proved that the blood pump rotor exhibited a good suspension stability, and the maximum offset under the impact external fluid was no more than 2 μm.

The trajectory monitoring method of hydrodynamic suspension bearing based on laser-ranging technology

“…Moreover, based on the optical dispersion principle, we introduced a spectral confocal displacement sensor to the axial displacement measurement of a suspension bearing, and the absolute error was less than 0.05% [38]. However, measurement instability is a concern because dispersion, multiple refractions, and reflections may weaken the monochromatic light signal.…”

“…However, measurement instability is a concern because dispersion, multiple refractions, and reflections may weaken the monochromatic light signal. In addition, concerning methodology, these studies focused on motion capture in only one direction [33,38]; thus, an efficient scheme for two-dimensional trajectory measurement needs to be further developed. Alternatively, lasers with monochromatic characteristics, high brightness, and directionality have been widely used in various fields, such as industrial production and scientific research.…”

Design and Control of Advanced Mechatronics Systems

“…The study of [5] aimed to envisage and design the magnetic suspension system coupled with a single-winding bearingless motor and permanent magnet bearings, establish the theoretical models of axial force and electromagnetic torque, and calculate the stiffness of the magnetic suspension system at the equilibrium point. Addressing the problem of the negative axial stiffness of the magnetic suspension system being negative, which leads to the instability of the suspension rotor, the hydrodynamic bearing structure was proposed and designed, and the critical stiffness to realize the stable suspension of the rotor was obtained based on the stability criterion of the rotor dynamics model.…”