Seals Based on Magnetic Fluids for High Precision Spindles of Machine Tools

摘要

The research work reported in this paper is focused on the use of magnetic fluids as active elements in seals for improving sealing capacity and minimizing friction torque, with application to the spindles of high precision machine tools. The prototype design was optimized following numerical computation of the magnetic field in the rings of the seal. Two magnetic fluids were analyzed for their use in the seals: a ferrofluid and magnetorheological fluid. The sealing capacity of the MRF based seals was higher than 45 kPa per ring, but the friction of the seal in the bearing was 8 N center dot m, too large for the use in precision spindles of machine tools because of the energy consumption and heat generation. The ferrofluid seal achieved sealing capacity around 9 kPa per ring, good enough to be used in the spindles of machine tools, with a friction 0.25 N center dot m and low energy consumption. The feasibility of using ferrofluids for developing high performance seals for high precision spindles and the validity of the simulation models has been demonstrated experimentally.