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The MEMS Handbook (1st Ed) - M. Gad el Hak Part 4

Tham khảo tài liệu 'the mems handbook (1st ed) - m. gad el hak part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Two options exist 1 hydrostatic externally pressured thrust bearings in which the fluid is fed from a high-pressure source to a lubrication film and 2 hydrodynamic where the supporting pressure is generated by a viscous pump fabricated on the surface of the thrust bearing itself see Figure 9.9 . Hydrostatic bearings are easy to operate and relatively easy to fabricate. These have been successfully demonstrated in the MIT Microengine program Frechette et al. 2000 the thrust bearing is shown in Figure 9.8 which shows an SEM of the fabricated device cut though the middle to reveal the plenum restrictor holes and bearing lubrication gap which is approximately 1 pm wide. Key to the successful operation of hydrostatic FIGURE 9.8 Close-up cutaway view of microthrust bearing showing the pressure plenum on top feed holes and bearing gap faintly visible . SEM courtesy of C.-C. Lin. FIGURE 9.9 Schematic of hydrodynamic thrust bearings and predicted performance stiffness in N m vs. axial eccentricity for a typical spiral-groove thrust bearing for use in a high-speed MEMS rotor. 2002 by CRC Press LLC Two options exist 1 hydrostatic externally pressured thrust bearings in which the fluid is fed from a high-pressure source to a lubrication film and 2 hydrodynamic where the supporting pressure is generated by a viscous pump fabricated on the surface of the thrust bearing itself see Figure 9.9 . Hydrostatic bearings are easy to operate and relatively easy to fabricate. These have been successfully demonstrated in the MIT Microengine program Frechette et al. 2000 the thrust bearing is shown in Figure 9.8 which shows an SEM of the fabricated device cut though the middle to reveal the plenum restrictor holes and bearing lubrication gap which is approximately 1 pm wide. Key to the successful operation of hydrostatic FIGURE 9.8 Close-up cutaway view of microthrust bearing showing the pressure plenum on top feed holes and bearing gap faintly visible . SEM courtesy of C.-C. Lin. FIGURE .