Design And Research On The Magnetic Bearing System

Magnetic bearing is different from the general bearing supporting the rotor by magnetic force based on feedback control theory. There are a series of special performances such as no friction, no abrasion, high speed, high degree of accuracy and low power consumption. Therefore,it can be widely used in the high speed and high degree of accuracy rotaries. It is a typical mechatronics product with high technology and high added value. However,because magnetic bearing technology relates to many subjects like mechanics,electronics,sensors,control and computers, there are a series of theories and methods that must be studied before the magnetic bearing can be used in the industrial products in our country. It's generally in the phase of lab study for domestic magnetic bearing study.This thesis briefly introduces the development situation and the study status of magnetic bearing as well as its main theories. Then,the main design process of magnetic bearing's structure design is given and the design process of stator's structural parameters is illuminated especially. A mixed innovative supporting system is advanced which uses both magnetic bearing and traditional bearing to support the spindle. Large rigidity and damping are needed in the front end of spindle,so the magnetic bearing is used here. A couple of angular contact ball bearings are used in the back end of spindle. It is the advantages that assuring the high rigidity and high damping of magnetic bearing,simplifying the structure and saving the cost. For the assistant bearing,a new-style assistant bearing of magnetic bearing system is designed which is controlled to move by an electromagnet. The engagement between the assistant bearing and the spindle is smoother and its service life is enhanced. So there is good use value for it. The design process of assistant bearing is given,and the design processes of the electromagnet and spring are illuminated especially. The three-dimensional model is created to analyze the spindle's modality using the finite element analysis method. The analysis result shows that the system would work without sympathetic vibration under the normal working rotational speed.