Dynamic Coefficients Identification of Water-Lubricated Hybrid Bearings Used in High-Speed Spindles with Different Excitation Methods

Figure 4

Comparative results of the stiffness coefficients by noncontact harmonic excitation: two rotating speeds (6,000 r/min and 9,000 r/min), three supply pressures (1.2 MPa, 1.5 MPa, and 1.8 MPa), and two exciting frequencies (4 Hz and 60 Hz).

(a) Direct stiffness,

(b) Cross stiffness,

(c) Cross stiffness,

(d) Direct stiffness,