The Two-Pad: A Novel Gas Foil Bearing for Fuel Cell Vehicles

Reducing costs and improving durability are essential factors for commercializing gas foil bearings, crucial components of fuel cell vehicle air compressors. In this paper, a two-pad gas foil bearing is proposed. By reducing the number of top foils, adopting a symmetrical design, and eliminating the welding step, the cost of processing and assembly is reduced, and the potential source of failure caused by welding is eliminated. The feasibility of the two-pad gas foil bearing was verified through testing on a commercial fuel cell vehicle air compressor. Then, durability testing was performed in accordance with fuel cell vehicle usage requirements, including an accelerated random vibration test equivalent to 6,000 h of on-board operation and a 200,000-cycle start-stop test. These tests simulated the damage caused to the bearings during fuel cell vehicle operation and start-stop periods, respectively. The durability test results indicated that the two-pad gas foil bearing provides good start-stop durability but insufficient durability against on-board random vibration. The failure causes were analyzed, and improvement measures were proposed. Our findings can be utilized to guide the manufacturing of low-cost and highly durable gas foil bearings.