Vertical centrifugal water pump convenient to maintain

The vertical centrifugal water pump convenient to maintain comprises a power mechanism and a centrifugal mechanism, the power mechanism comprises a three-phase alternating-current asynchronous motor, a supporting frame, an output shaft coupler, a bidirectional coupler and an impeller coupler, the supporting frame is in a three-section type, the center of the supporting frame is hollowed out, and the supporting frame is not sealed. The two ends of the bidirectional coupler are connected with the output shaft coupler and the impeller coupler respectively, the centrifugal mechanism comprises a machine body, a machine cover, a bearing seat, an impeller shaft and a centrifugal impeller, the machine body comprises a base, a centrifugal cavity above the base, a liquid inlet and a liquid outlet, the liquid inlet and the liquid outlet are formed in the two ends of the machine body, and an oil cup is installed on the side wall of the bearing seat. And a sealing shaft sleeve is arranged between the impeller shaft and th