Identification of Characteristic Parameters for Hydrostatic Bearings

Abstract

This study proposes a method to identify the characteristic parameters of hydrostatic bearing. When load or supply pressure changed, the inlet and outlet pressures of restrictor, flow rate and worktable displacement are examined for establish identification equations. The practical values of the characteristic parameters can be obtained by minimizing the differences between measure flow rate and identify flow rate. The differences between practical and design values of these parameters can be used to calibrate design parameters for satisfying the requirements.

Identification of design parameters for spool-type restrictors

“…The detailed descriptions of the equipment used in this study to measure the characteristics of SACS restrictors can be seen in Kang et al., 8 which is composed of an open-type hydrostatic bearing with four upward recesses and two recesses on both sides. A worktable mounting on the hydrostatic bearing is subjected to load for changing pressures of upward recesses, which are compensated by the spool-type restrictors individually.…”

“…By using the same manner as references, 7,8 the pressurized lubricant which is measured as Psk for the k th supply pressure passes through each restrictors and flows into the j th recess with outlet pressure Prj and flow rate Q j , and finally flow out from the clearance and return to oil reservoir. The measurement range and sensitivity of pressure meters used to measure the pressures of upstream and downstream of restrictors are 0–50 bar and 0.15682 V (kg/cm), respectively, and the output is electric current which is necessarily transformed from 4 to 20 mA by resistance 250 Ω to voltage 1 V–5 V for computer input.…”

“…Also, we can fix load W but change P s , and each P r is measured. Substitute these measured data into equations (8) and 9to determine and . In experiments, the temperatures measured at outlet and inlet are maintained with 0.5 C variation, and the inlet temperature of SACS is maintained to be 20 AE 0.5 C. The variations of measured working pressure with respect to measured flow rate are shown in Figure 3 and Table 1 for four restrictors.…”

“…Using the same manner, Kang et al. 8 presented the identification of parameters for hydrostatic bearing. The regressive values of the design parameters can be obtained by minimizing the differences between measure and identified flow rate.…”

“…Kang et al 7 presented an approach to identify the restriction parameter and membrane deformation coefficient of single-action membrane-type restrictor by experimental results. Using the same manner, Kang et al 8 presented the identification of parameters for hydrostatic bearing.…”