Hydrostatic Bearing with High Bulk Modulus Fluid

Hydrostatic bearing systems are used in machine tools due to the high damping capacity, the high stiffness, and the smooth motion. Demands for higher stiff bearing system have recently increased in various industrial sectors. In order to achieve higher stiffness of the bearing system, working fluid with lower compressibility should be used. High bulk modulus fluid with very low compressibility has been recently developed. This paper presents a hydrostatic bearing system using high bulk modulus fluid. The basic characteristics of the bearing are evaluated with an experimental setup for evaluating the bearing system and then compared the degassed oil with the conventional oil. Furthermore, static and dynamic characteristics of the bearing system were evaluated and compared with that of a conventional hydrostatic bearing. Experimental results confirmed that the high bulk modulus fluid enhances the performance of the hydrostatic bearing.

Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and it is found that it increases the hydrodynamic performance when applied to a stiff bearing, whereas the liner has practically no influence on the flexure journal bearing's performance.