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

Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 255
Author(s):  
Peng Shen ◽  
Yiwen Wang ◽  
Yun Chen ◽  
Pengqiang Fu ◽  
Lijie Zhou ◽  
...  

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.

2020 ◽  
Vol 64 (1-4) ◽  
pp. 977-983
Author(s):  
Koichi Oka ◽  
Kentaro Yamamoto ◽  
Akinori Harada

This paper proposes a new type of noncontact magnetic suspension system using two permanent magnets driven by rotary actuators. The paper aims to explain the proposed concept, configuration of the suspension system, and basic analyses for feasibility by FEM analyses. Two bar-shaped permanent magnets are installed as they are driven by rotary actuators independently. Attractive forces of two magnets act on the iron ball which is located under the magnets. Control of the angles of two magnets can suspend the iron ball stably without mechanical contact and changes the position of the ball. FEM analyses have been carried out for the arrangement of two permanent magnets and forces are simulated for noncontact suspension. Hence, successfully the required enough force against the gravity of the iron ball can be generated and controlled. Control of the horizontal force is also confirmed by the rotation of the permanent magnets.


2011 ◽  
Vol 5 (6) ◽  
pp. 1226-1237
Author(s):  
Kazuya NISHIMURA ◽  
Takeshi MIZUNO ◽  
Yuji ISHINO ◽  
Masaya TAKASAKI ◽  
Yasuhiro SAKAI

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