||The steady and dynamic characteristics of the hydrodynamic lubrication for the herringbone-grooved journal bearing with plain sleeve (GJPS) and plain journal bearing with grooved sleeve (PJGS) are analyzed under various design parameters, including the ratio of groove width, ratio of groove depth, groove angle, and position of groove. In the previous studies, the equation of film thickness used by GJPS and PIGS is the same. It has been corrected by this study to obtain an accurate film thickness for GJPS. Reynolds equations suitable for all groove angles are derived using the coordinate conversion, so that it can be applied to obtain the steady state solution under various design parameters. A perturbation method is used to linearize the nonlinear dynamic Reynolds equations, so that the transient state solutions and dynamic characteristics under various design parameters can be obtained. Effects of the design parameters on the load capacity, stiffness coefficient, damping coefficient and critical mass are investigated.|
Numerical results show that GJPS and PJGS have the greatest load capability at ratio of groove width 0.5, eccentricity ratio 0.2, ratio of groove depth 1.0, and groove angle 33 degrees, but PJGS has higher load capability than that of GJPS. At ratio of groove width 0.5, eccentricity ratio 0.3, ratio of groove depth 1.0, and groove angle 28 degrees, stiffness and damping coefficients achieve a maximum value, but PJGS has higher values of the stiffness and damping coefficients than that of GJPS. Moreover, their critical mass and onset whirl ratio achieve minimum with most stable, but PJGS is more stable than that GJPS.