The application of magnetic bearings in high speed machine tool spindle
May 5, 2014 8:16pm CST
Magnetic bearings used in 100000 RPM speed can be obtained on the high-speed spindle, on the one hand, can improve the effect of surface processing, on the other hand it is greater than that of traditional bearing service life. Although the technology is still in the prototype testing phase, but a lot of advantages has been fully reflected. Its performance is not the effect of heat, no wear and tear, in the case of overload can be automatically shut down. The traditional bearing for the spindle radial or axial support, allows the relative movement between inner ring and outer ring. Inner ring and outer ring are connected by a ball or roller, support also in between the three. The oil film bearing no ball or roller, it USES pressure oil for lubrication or cooling. The above two kinds of bearing has several one hundred years of application history. Magnetic bearings for rotating parts support way is different from the above two products. Magnetic bearing is a kind of non-contact bearing, it through the electromagnetic force between the moving parts are suspended in the fixed part. Also means that there is no friction, no wear and tear, and higher stability, and can obtain higher speeds. Electromagnetic force is mainly related to the size of the current and gas gap, gap sensors to collect data, the size of control system based on the input signal to adjust output current. Magnetic bearing is mainly composed of three parts: To provide support for the spindle bearing and sensor: bearing, sensor for gathering location signals. Control system: be responsible for providing power, and according to the feedback signal to calculate the correct corrective force, to drive the different direction of the controller. A system: be responsible for calculation and output feedback signal. Magnetic bearing is the main drawback is that: large, need power supply, as well as the complex structure and algorithm. In recent years, countries, internal and external research and development of ceramic bearing has achieved fruitful results, and substantial progress. In machine tools, chemical, aerospace and other fields has been applied and play a magical effect. With complete ceramic bearing steel bearing has the following advantages of magic: 1, high speed and acceleration, can run under the condition of dn value of more than 3 million, and skid, can reduce wear and fever; 2, long service life, wear-resisting, full ceramic bearing fatigue life is 10 to 50 times longer than the whole of the steel bearing one, hybrid ceramic bearing, the life also is higher than all steel bearing's life for 3 to 5 times the left and right sides; 3, the lubrication rarely - low friction coefficient of ceramic material, ceramic bearing is lubricated by oil, in lube oil is thinning or boundary conditions, its lubricating ability is still not less than the traditional steel bearings commonly used lubricants; 4, resistant to abrasion, due to the ceramic materials as inert material, so the more resistant to corrosion and wear; 5, rigid - from ceramic materials of high elastic modulus, the rigid steel bearing 15-20% larger than normal; 6, high temperature resistant, can full ceramic bearing in 500. C above temperature working; 7, low torque, according to the structure, reduce 1/3 of the ceramic bearing torque; 8, non-magnetic non-conductive, ceramic bearing is not affected by magnetic, electrical damage. With the deepening of the research and manufacture large quantities of technical breakthrough, ceramic bearing in high speed, high temperature, corrosion resistance, and other fields of application prospect will be very considerable.