Engineering machinery and equipment is a major component, while the planetary gear http://www.yousheng1688.com is the most common mechanical equipment, one of the most important components, which directly affects the price of construction costs, and the current market As to the quality of the planetary gear reducer worm price is based on unscientific, because we can not measure the quality of the size of the planetary gear's ability, they can not scientifically compare different models, different types of planetary gear unit price, so study investigated the planetary gear The scientific basis of the price is very necessary. Planetary Gearheads quality and describe the relationship between output torque planetary gear from nine parameters, in addition to quality parameters, the remaining parameters are inherent mathematical relationships, and it is the quality of this parameter determines the current market price of the planetary gear unit.