Speed reducer

The utility model provides a speed reducer which comprises a box body and an input shaft, one end of the input shaft extends into the box body, and the other end of the input shaft is connected with a coupler. One end of the first sealing mechanism is connected with the box body, the other end of the first sealing mechanism is connected with the coupler, and the first sealing mechanism can seal the box body; the gearbox further comprises a second sealing mechanism, the second sealing mechanism is located between the box body and the first sealing mechanism, one end of the second sealing mechanism is connected with the first sealing mechanism and the box body at the same time, and the other end of the second sealing mechanism is connected with the input shaft. Maintenance can be achieved under the condition that the coupler is not detached, and maintenance convenience is improved. 本实用新型提供一种减速机，包括：箱体和输入轴，所述输入轴的一端伸入至所述箱体内，所述输入轴的另一端与联轴器连接；第一密封机构，所述第一密封机构的一端与所述箱体连接，所述第一密封机构的另一端与所述联轴器连接，所述第一密封机构能够对所述箱体进行密封；还包括第二密封机