The Design And Performance Research Of A Novel Ferrofluid Journal Bearing Of Controlled Damping

The vibration of machines play an important role in machining precision, and the vibration of the bearings mounted in machines will directly constrain the quality of products.Therefore, it is a useful way to improve the machining precision by damping the vibration of the bearings mounted in machines. Magnetic fluid journal bearing is a kind of active vibration-controlling sliding bearings. It adopts the ferrofluid, a new type of functional material belonging to damping-controllable fluid, as the lubricant medium. As it has many merits such as simple structure that there is no need to design its circulating oil system, the controllable viscosity and the free-frication performance of its lubricant, and the self-sealing performance in the presence of external magnetic field, it is possible to be an active vibration-controlling journal bearing, which is benefit to the development of industrial automation.This paper presents an experiment research of the vibration-controlling performance for ferrofluid journal bearings; a new kind of the ferrofluid journal bearing whose magnetic field created by a solenoid in it was designed and manufactured. Firstly, making use of the damping-controllable fluids-magnetic fluids, a new type of damping-controllable magnetic journal bearings was designed and the magnetic circuit and sealing was put a great eye on; the magnetic circuit of the damping-controllable journal bearings was analyzed by the magnetic flux leakage coefficient method and the structural optimization parameters were calculated by Newton optimal method. Then referring to the designed parameters, a model of magnetic analysis for the magnetic fluid journal bearings was built and calculated by Ansys finite element simulation software; a relationship between the inner magnetic induction intensity and the external applied direct current was plotted by the method of changing the applied current load on the model to calculate the corresponding magnetic induction intensity.Secondly, through the theory analysis and validation , the designed bearings were made and the performance test system was established based on eddy current displacement sensors?data acquisition card and servo motors etc. Finally, do an experiment on the damping-controllable performance of the magnetic fluid journal bearings with the built test rig, and sort the data from the experiment to plot the amplitude diagram of various conditions where there are different currents of circuits with different rotation speed of motors. Research suggests that there is an obvious damping effect on journal bearings by means of using magnetic fluids as lubricant and this paper make a great contribution to the development of magnetic fluid journal bearings.