Complete determination of the dynamic coefficients of coupled journal and thrust bearings considering five degrees of freedom for a general rotor-bearing system
- 250 Downloads
A complete method is presented for calculating the stiffness and damping coefficients of coupled journal and thrust bearings of a general rotor-bearing system considering five degrees of freedom. The Reynolds equations and their perturbation equations were derived by linearization of the bearing reaction with respect to the general five degrees of freedom, i.e., the tilting displacements and angular velocities as well as the translational displacements and velocities. The Reynolds equations and their perturbation equations were transformed into finite element equations by considering the continuity of pressure and flow at the interface between the journal and the thrust bearings. The Reynolds boundary condition was included in the numerical analysis so as to simulate the phenomenon of cavitation. The stiffness and damping coefficients of the proposed method were compared with those found from a numerical differentiation of the loads with respect to the finite displacements and velocities of the bearing center. It was shown that the proposed method may be used to calculate the dynamic coefficients of coupled journal and thrust bearings more accurately and efficiently than the differentiation method. The tilting motion was also been found to play an important role in the determination of force and moment coefficients.
KeywordsHard Disk Drive Journal Bearing Reynolds Equation Thrust Bearing Perturbation Equation
- Lund JW, Thomsen KK (1978) A calculation method and data for the dynamic coefficients of oil-lubricated journal bearings. Topics in fluid journal bearing and rotor bearing system. ASME, New York, pp 1–28Google Scholar
- Oh SM, Rhim YC (2001) The numerical analysis of spindle motor bearing composed of herringbone groove journal and spiral groove thrust bearing. KSTLE Int J 2(2):93–102Google Scholar
- Rahman M, Leuthold J (1996) Computer simulation of a coupled journal and thrust hydrodynamic bearing using a finite-element method. In: Proceedings of 25th Annual IMCSD Symposium, The Society, San Jose, pp 103–112Google Scholar
- Zang Y, Hatch MR (1995) Analysis of coupled journal and thrust hydrodynamic bearing using a finite-volume method. ASME AISPS 1:71–79Google Scholar