Static performance of the aerostatic journal bearing with grooves

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 presented.), circumferential groove length (Formula presented.), orifice diameter d_f, groove depth g_h, misalignment angles (Formula presented.) and (Formula presented.) on the load capacity (Formula presented.), stiffness (Formula presented.), and gas flow rate (Formula presented.) 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 presented.), stiffness (Formula presented.), and gas flow rate (Formula presented.) are examined in the simulations. It is revealed from the simulations that the proper value of axial groove length (Formula presented.) to obtain a better static performance varies from 1/8 to 1/2 when d_f varies between 0.11 and 0.29 mm, respectively. Therefore, a larger load force and stiffness can be obtained if (Formula presented.) is chosen to be 1/4, when diameter of the bearing orifice d_f equals 0.17 mm. It is also suggested that (Formula presented.) be chosen from the range of 1/6 and 1/3 to obtain a better static performance and a smaller gas flow rate. (Formula presented.) decreases with an increase in d_f when (Formula presented.) is set to be 1/8. However, the load force (Formula presented.) increases with an increase in d_f when (Formula presented.) varies from 3/8 to 1/2. (Formula presented.) has a significant influence on the changes of (Formula presented.) with d_f when (Formula presented.) is set to be constant. Therefore, d_f should be selected according to (Formula presented.) for an optimal design. The increase of misalignment angle (Formula presented.) leads to an increase in the load force (Formula presented.). (Formula presented.) has little influence on the load force (Formula presented.). Misalignment angles (Formula presented.) and (Formula presented.) have little influence on stiffness (Formula presented.) and gas flow rate (Formula presented.). Therefore, it is preferable if (Formula presented.) is larger than 0 rad.