The dimidiate frequency of early oil whirl was found clearly from HHT time-frequency spectrum, which magnified the parameter of oil whirl fault and provided information for early fault diagnosis.

• 该方法在早期油膜涡动中能够更加清晰地发现涡动二分频的存在，放大了涡动的故障特征，为早期故障诊断提供了方便。