Novel leakage-proof oil return structure for construction lifting speed reducer

The utility model discloses a novel leakage-proof oil return structure for a construction lifting speed reducer, and belongs to the technical field of construction lifting speed reducers. Comprising a motor, a reduction gearbox and a front cover for installing the motor on the reduction gearbox, a motor shaft in the motor drives a gear pair in the reduction gearbox to be in meshing transmission, a bearing seat and an oil seal seat are arranged on the inner side of the front cover in a protruding mode, an inner ring of a bearing of the motor is supported on the motor shaft, and an outer ring of the bearing is supported on the bearing seat. The sealing structure is characterized in that a motor side oil seal and a reduction gearbox side oil seal are sleeved on a shaft section of the motor shaft, which is positioned on the bearing and the shaft end, at an interval, outer rings of the motor side oil seal and the reduction gearbox side oil seal are matched with an oil seal seat, and the motor side oil seal, the re