Dynamic Characteristic Analysis Of Herringbone Grooved Hydrodynamic Sliding Bearing And Rotor System

With the penetrating of industrialization and modernization process, modern machinery are increasingly designed in high speed and high power. Sliding bearings are widely used as support in high-speed machinery, whose performance has important influence on rotating machinery. The structure of bearing plays a critical role in the performance of bearing. Spiral oil wedge bearing is a novel bearing which could effectively improve the dynamic and thermal characteristics of bearing. Recently, the herringbone grooved bearing is being applied more broadly. In this paper, the lubrication performance of herringbone grooved bearing is simulated and analyzed.The static and dynamic characteristics are studied. Also, the stability and dynamic characteristics of bearing and rotor system are analyzed. All the above work can provide basis for the design of appropriate supporting structure for high-speed roror system.The main work and results included in the thsis are as follows:1. By means of the finite differential method, the Reynolds equation is solved and the static characteristics of herringbone grooved hydrodynamic journal bearing are numerically analyzed by presenting the circumferential and axial pressures. Using Matlab,the influences of parameters such as the eccentricity, width and diameter ratio of bearing, rotating speed, spiral angle, depth and number of grooves, on the static characteristics of herringbone grooved bearing are discussed. The results indicate that the pressure, and carrying capacity as well, of herringbone grooved bearing will decrease with the increase of groove number and depth.2. The dynamic performances of herringbone grooved bearing when it was given disturbance are investigated.The unsteady Reynolds equation under oblique coordinate system is solved using pressure disturbance method.And the dynamic characteristic coefficients are obtained using numerical integeral method.Then the influence rules of operating parameters and structure parameters of herringbone grooved bearing to the stiffness and damping coefficients are obtained.3. The mechanism of unstable motion of sliding bearing is analyzed. Through solving the instability speed of single disk rotor system with bearing of different structures,the influence of structure parameters of bearing to the instability speed are studied. According to the results,the stability of herringbone grooved bearing is better compared with normal bearing.Then the dynamic performance of bearing and single disk rotor system are investigated. The critical speed and and unbalanced response are solved.