Abstract: Continuous and long-term overrunning with high speed is hard to accomplish for traditional overrunning clutches due to wearing and heat. Chain-ring overrunning clutch is a kind of friction overrunning clutch invented in recent years. With completely new working principle, it has higher performance in many ways such as load capability and life. While in overrunning state it may work like sliding bearing with hy-drodynamic lubrication. The wearing and heat are quite low since the two working surfaces may be contactless. Experi-ments show that the overrunning performance of chain-ring overrunning clutch is excellent. Thus it can be widely used in applications where high performance of overrunning is desired.

Key words: Hydrodynamic lubrication, Chain-ring, Clutch, Overrunning