Static performance of the aerostatic journal bearing with grooves

Abstract

Aerostatic bearings are widely employed in precision machines due to their properties of low friction, low heat conduction, and long-life operation. In this work, static performance of the journal bearing with rectangular grooves is investigated numerically. The effect of geometrical parameters such as axial groove length [Formula: see text], circumferential groove length [Formula: see text], orifice diameter df, groove depth gh, misalignment angles [Formula: see text] and [Formula: see text] on the load capacity [Formula: see text], stiffness [Formula: see text], and gas flow rate [Formula: see text] are analyzed systematically. The resistance network method (RNM) is utilized to solve the Reynolds equation required in the analysis. Performance parameters including pressure distribution P, load force [Formula: see text], stiffness [Formula: see text], and gas flow rate [Formula: see text] are examined in the simulations. It is revealed from the simulations that the proper value of axial groove length [Formula: see text] to obtain a better static performance varies from 1/8 to 1/2 when df varies between 0.11 and 0.29 mm, respectively. Therefore, a larger load force and stiffness can be obtained if [Formula: see text] is chosen to be 1/4, when diameter of the bearing orifice df equals 0.17 mm. It is also suggested that [Formula: see text] be chosen from the range of 1/6 and 1/3 to obtain a better static performance and a smaller gas flow rate. [Formula: see text] decreases with an increase in df when [Formula: see text] is set to be 1/8. However, the load force [Formula: see text] increases with an increase in df when [Formula: see text] varies from 3/8 to 1/2. [Formula: see text] has a significant influence on the changes of [Formula: see text] with df when [Formula: see text] is set to be constant. Therefore, df should be selected according to [Formula: see text] for an optimal design. The increase of misalignment angle [Formula: see text] leads to an increase in the load force [Formula: see text]. [Formula: see text] has little influence on the load force [Formula: see text]. Misalignment angles [Formula: see text] and [Formula: see text] have little influence on stiffness [Formula: see text] and gas flow rate [Formula: see text]. Therefore, it is preferable if [Formula: see text] is larger than 0 rad.