Novel Diaphragm-Control Restrictor for Precision Hydrostatic-Bearing Spindle
A novel diaphragm-control restrictor (DCR) is proposed for improving the performance of the hydrostatic-bearing spindle used in machine tools. The unique function of the proposed DCR is the wide adjustability of its restrictor characteristic. A two-step restriction system is adopted for the DCR; a spool restrictor is used as the first step restrictor. By changing the restrictor resistance of the spool restrictor, the effect of the active control in the DCR, the second step restrictor, can be altered. The proposed DCR is incorporated into a hydrostatic bearing supporting a precision spindle, and the performance of the bearing is analyzed. Numerical and experimental analyses show that the stiffness of the hydrostatic bearing with the proposed DCR can be five times as large as a conventional hydrostatic bearing of the same dimensions. Analysis of the dynamic compliance shows that the effect of the active control can be observed up to 20Hz. These results show that the proposed DCR is useful for improving the performance of the hydrostatic-bearing spindle in precision applications.
W.B. Lee, C.F. Cheung and S. To
H. Mizumoto et al., "Novel Diaphragm-Control Restrictor for Precision Hydrostatic-Bearing Spindle", Key Engineering Materials, Vol. 516, pp. 463-468, 2012