To provide a dust-proof structure of a sleeve bearing, preventing oil contaminant from staying to reduce friction and noise due to rotation and further lengthen the use life of a motor by installing a sleeve bearing and a dust-proof cushion in the interior of a shaft tube and forming at least one oil return groove between the sleeve bearing and the dust-proof cushion.

This dust-proof structure is composed of the shaft tube, the sleeve bearing and the dust-proof cushion. The shaft tube can store the sleeve bearing and the dust-proof cushion. A shaft of the rotor is bored in a shaft hole of the sleeve bearing. The dust-proof cushion is provided on the upper side of the sleeve bearing, thereby preventing dust from being gathered in the sleeve bearing. At least one oil return groove is formed between the dust-proof cushion and the sleeve bearing, thereby heightening circulation and flowing of oil in the sleeve bearing, and keeping the lubrication between the sleeve bearing and the shaft.