Abstract

Nowadays, there is a trend in the downsizing of rotating machinery accompanied by increasing rotational speed. Oil-free, high-speed rotating machinery supported by foil bearings (FBs) has emerged as an effective solution to address this trend. However, the application of FBs faces two significant challenges, namely the load capacity and stability. Along these lines, the current status of the FBs in industrial applications and academic research was summarized in this work. Various theoretical models of FBs are discussed, and the processing methods and test rigs used for FBs were illustrated. The structural improvements aimed at enhancing the load capacity and rotor stability were summarized and the active/intelligent FBs were introduced. The opportunities for future developments of FBs in the fields of theoretical analysis, design, control, etc. were also discussed.