The base part is composed of supporting sleeve, rolling bearing, lower bearing cover, lower sealing ring, shaft sleeve, gasket, oiling device and base. The base is used for the positioning of the entire rotor shaft. The support sleeve is used to support the two rolling bearings and the lower bearing cover. Spherical roller bearings are mainly used to bear axial force. Thrust spherical roller bearings mainly bear radial force. Add a spacer between the two bearings to separate the two bearings to avoid direct contact between the two bearings, which will affect the life of the two bearings. The annular seal formed by the lower bearing cover and the lower sealing ring is used to block the dust in the cylinder from entering the bearing.