DEVELOPMENT AND TESTING OF THE POWER TRANSMISSION SYSTEM OF A CRAWLER ELECTRIC TRACTOR FOR GREENHOUSES

Greenhouses are among the most rapidly developing sectors of the Chinese agricultural industry, and they require considerable mechanization. Currently, the machinery used in greenhouses mainly include micro cultivators powered by internal combustion engines. The micro cultivators have various problems such as small output power, low operating efficiency, and poor quality. Also, they harm the growth environment of crops and the working environment of farmers due to gas emissions and noise. In this study, a crawler electric tractor suitable for greenhouses is proposed. It can function in small working areas and narrow working spaces. The electric tractor is suitable for towing, transportation, lifting, and power output. A power transmission system scheme was designed for the electric tractor and a parameter matching method for the core components of the power transmission system is proposed. The prototype of the electric tractor was manufactured and underwent field rotary tillage, field transport, and plowing energy consumption tests. The results of rotary tillage and transportation testing showed that the operating parameters such as the depth and width of rotary tillage and transportation speed met the design requirements, which validated the matching of core components of the power transmission system and the operating performance of the prototype crawler electric tractor. The mean rotary tillage depths of the prototype on the left side and the right side are 11.0 and 12.1 cm, respectively. The mean width is 113 cm. The mean speed of rotary tillage is 4.99 km h(-1). The measured speed of the prototype in the field is within the speed demand range at gears I, II, and III. According to the results of plowing energy consumption test, the mean electrical energy consumption of plowing one mu of land was 5.60 kW h mu(-1), which showed that the prototype crawler electric tractor had good economic performance. To sum up, the prototype of the electric tractor for greenhouses manufactured is economic and practical.