Protection seal mechanism of underwater excavating pump bearing

The utility model discloses a protective sealing mechanism for a bearing of an underwater excavating pump. The sealing mechanism comprises a seal disk which is connected with the shell body of the underwater excavating pump and coaxial with the bearing thereof, a seal hole formed at the axle center of the seal disk, a shaft sleeve which penetrates the seal disk and arranged at the center of the seal hole along an axial line, a seal ring group arranged in an annular cavity formed by the shaft sleeve and the inner wall of the seal hole, and a seal ring gland arranged on the outer end surface of the seal disk. The protective sealing mechanism is characterized in that the seal ring group is composed of three seal rings, an opening of the inside seal ring is arranged inwards, and the openings of the middle and the outside seal rings are arranged outwards; a spacer ring is arranged between the middle and the outside seal rings; an annular oil groove is formed on the outer wall of the spacer ring, and a through-hole