The Design Of Permanent Magnet Bearings For HBM Vertical Axial Flow Pump

The proportion of Vertical axial flow pump and mixed flow pump is large in China. And the grindability guide bearing is the most critical, fragile parts of large pump. To achieve reliable operation, the problem rooted from high-speed rotor supported is needed to be addressed. Mechanical contact bearings, lubrication and the need to maintain the highest limit of its speed and service life, has become the bottleneck of traditional high-speed driving. Magnetic bearings have no friction, no wear, no lubrication and sealing, no power, no pollution, high speed, high precision, long life, reliable operation and a series of good quality. Therefore, the study of magnetic field and magnetic force becomes more important.At present, the theoretical analysis and design for the permanent magnetic bearing is far from mature. Existing research studies for the double-loop permanent magnet bearings, and they are complex numerical model. And it is lack of new structures of permanent magnet bearings and magnetic bearings magnetic explicit analytical model, guidding the permanent magnet bearing the inconvenience structural design and optimization. This article which studies nested multi-ring Halbach array permanent magnet magnetic bearings explicit analytical model has important practical significance.This major work done by the following:1) It is known that most of the load size and direction of radial points are random by analyzing the axial guide bearing load distribution. This makes the problem too complicated and difficult to solve. Because the randomness of the direction of sub-load effect on the total load is larger than the size of the total load of random, it aproximates that all points equal to its maximum payload size. And assume that the random changes, independent of each other, in the direction of the sub-load in all directions uniformly distributed probability density. It is of sub-load which is random changes of direction bearing on the overall effect of lead.2) Halbach array of permanent magnet bearings is nested in the form of a rotating magnetized permanent magnet rings stacked structure. First, based on the equivalent magnetic charge method, a single pair nested permanent magnet ring structure of mathematical modeling is analied. According to the linear superposition principle, a single wavelength of the nested structure of permanent magnet rings stacked mathematical model is established. Then, using molecular current law, a single wavelength of Halbach array magnets explicit analytical capacity of the mathematical model is established. Then stiffness expressions are derived. Through programming and numerical computation, analysis and comparison with finite element software.It shows that the use of magnetic charge method based on equivalent single-ring structure of the nested permanent magnet model and analyze the method relative to the current method used to establish a single molecule of Halbach array magnets wavelength capacity of explicit analytical mathematical model errors large and complex calculation. However, using a single wavelength of Halbach array magnets bearing capacity of the mathematical model shows that explicit analytical function of various parameters have intuitive features. It is easy to optimize the design. And it is relatively finite element analysis results of error of about 5%.3) Halbach magnet array multiple wavelength capacity, and explicit expression of the stiffness expressions are derived and verified. It combines the best structural parameters of Halbach magnet relationship, the appropriate magnet structure is designed. It can meet the requirements of the magnetic force, stiffness index, and it is relatively finite element analysis results of error of 6%.