Sealing structure of speed reducer power output shaft of offshore platform operation mechanical arm

The utility model relates to a sealing structure of a power output shaft of a speed reducer of an offshore platform operation mechanical arm, which comprises a sealing end cover in a circular shape so as to be sleeved on a columnar end cover of the speed reducer; the power output shaft penetrates through the sealing end cover and the columnar end cover so as to be exposed out of the speed reducer shell; the bearing seat is embedded in the columnar end cover and is rotatably connected with the power output shaft, so that the power output shaft can rotate to output the power of the speed reducer; the first assembly ring is partially embedded in the columnar end cover and is positioned on the left side of the bearing seat to sleeve the power output shaft so as to limit the bearing seat; the second assembly ring is arranged on the power output shaft in a sleeving mode and located on the left side of the first assembly ring so as to be matched with the first assembly ring to seal the power output shaft and rotate