An adaptive morphological filtering and feature enhancement method for spindle motor bearing fault diagnosis

•A new AMF method of adaptive optimization of structural element parameters is proposed for effectively eliminating noise.•The TEO method is applied to the filtered signal of AMF for enhancing the higher harmonic components of fault frequency.•An improved filtering and feature enhancement method combined with the merits of AMF and TEO is proposed.•The two cases of spindle motors matched with different bearing materials in different fault degree verify the effectiveness.