Square tenon output and double-lug-hole mounting rotary speed reducer

The invention relates to a square tenon output and double-lug-hole mounting rotary speed reducer which comprises a base (1). The base (1) comprises a shaft casing (1.1) and a base ring (1.2). A worm (2) is arranged in the shaft casing (1.1). A bearing mounting base (1.3) is arranged on the inner side of the base ring (1.2), and an output square tenon (1.4) is arranged on the outer side of the base ring (1.2). The bearing mounting base (1.3) is sleeved with a rotary gear (3), and the worm (2) is engaged with the rotary gear (3). According to the square tenon output and double-lug-hole mounting rotary speed reducer, a square tenon output manner integrated with the base is adopted in output, transmission torque is large, and the shock resistance capacity is high. A double-lug-hole mounting manner is adopted, so that a mounting gap is small, and stability is good. The square tenon and the base are of an integrated structure, and the water prevention performance is good when the square tenon is mounted upwards. The overall structure is compact, carrying capacity is high, and the cost is low.