The Optimization Study Of Small Deep Plowing Machine Based On TRIZ Theory

The arable land in hilly areas of South China is about 40.32 million hectares. Due to the topographic restriction, most of these arable lands are small-size and irregular-shaped fields with high borders. Few large and medium-sized agricultural machines can work in such fields, so the micro tillage machine has come to be the main plowing machine owing to the characteristics of simple structure, convenient operation, low weight and small size. Micro tillage machine has greatly solved the tillage problems in these areas on the current conditions. But a new problem has arisen:because of its shallow tillage depth (usually around 16cm), long term usage of micro tillage machine has formed hard pan under plough layer, which seriously affects the growth and development of the crops. In this paper, we use the TRIZ theory to optimize the 1st generation Small Deep Plowing Machine, and then got a more perfect Small Deep Plowing Machine. And field experiments have been carried out in order to verify its operation effects and mechanical performances.Firstly, we use the TRIZ tools of system analysis and causal analysis to analyze the 1st generation Small Deep Plowing Machine. As a result, four root causes of its main problems have been found, they are:First, kind of drive. Gear drive has sufficient strength to ensure the reliability of the transmission system, but its big size and hug weight are disadvantageous to the machine operations, such as maneuverability in turning and penetrating ability of deep tiller knife; While chain drive has lighter weight and smaller size, but its strength is the key factor which influences the reliability of the transmission system. Second, tiller knife strength. To increase the tillage depth, the knife length has to be increased, but the longer the knife is, the easier it is broken. Third, deep tiller knife shape. To change the bending angle of deep tiller knife for increasing its penetrating ability would increase possibility of intertwining grass. Fourth, soil surface flatness. Due to the interference of working parts, considerable portion of soil accumulates on two sides of the deep tiller width after plowing, and forms a U-shape cross-section of soil surface.Then, based on above analysis, we made a contradictory analysis and use the problem solving tools to convert the four problems into TRIZ modes. After treatments of these modes we got their optimization solutions:First, using high strength chain drive to replace the gear drive of the 1st generation, decreased the size and weight of the transmission case, thus improved its maneuverability and penetrating ability. Second, use safety pin coupling and stiffness adjusting lever to prevent important parts from damage and increased machine’s reliability. Third, different shapes of deep tiller knifes were adopted to meet different soil conditions, so that to avoiding intertwining grass. Fourth, new scraper blades added improved soil surface flatness.At last, we have designed and made a new model Small Deep Plowing prototyping Machine in accordance with the optimization solutions, and carried out field experiments to verify its operation effect and mechanical performance. The test results show that the tillage depth is 30.8cm, the flatness is 4.36cm, the stability coefficient of tillage depth reaches 94.42%, and the engine runs smoothly without emitting black smoke. The new model Small Deep Plowing Machine has already come up to the designed standards.