The ZQA (PJ) series includes two types of hard tooth surface cylindrical gear reducers, one with a base (JB/T8905.2-1999) and the other with three support points (JB/Ta.1-199), which are widely used in the operating structure of various cranes under 50 tons. Suitable for transmission mechanisms on various mechanical equipment such as transportation, metallurgy, mining, petroleum, chemical, construction, and light industry. This series of reducers can be used for forward and reverse operation, with a gear transmission circumferential speed not exceeding 160 meters per second and an input shaft speed not exceeding 1500 r/min. The working environment temperature is -40 ℃ -+45 ℃. This reducer has nine transmission ratios, nine configuration forms, and three low-speed shaft end forms.