| Taking on the merit of saving load and time, enhancing yield, precision planting is the direction of planting. It is very important to improve the efficiency. So, precision metering device, as a key part, becomes a study hotspot especially its dropping frequency. According to its working principle, precision metering device can be divided into the pneumatic and the mechanical. Although the former has higher speed, it's complicated structure and higher price embarrass its popularization in our country. While the latter, having simple structure and lower price, can't fill the high working speed. So, we study its key technology so as to solve this conflict.The main tasks are as follows:1.Developing a new mechanical precision metering device for beans. We find that the main factor of embarrassing dropping frequency is that filling ratio will decrease when increasing seed-metering plate's rotate speed. Our new device adopts a new style filling hole and a new filling method that makes the seed filling the hole along the wall of the seed-metering plate , which will assure seeds filling. At the same time, we lay more filling hole in a circle. Furthermore, leaving out the cleaning structure and compelling dropping structure, this device is more simple.2.Setting up the models of working processes. The processes include filling, clearing, retaining and dropping. Which establish the basement for the computer stimulation optimized design.3.Bench testing on the new precision metering device. At first, large numbers of tests have been done to test seeds' fragmentation ratio. Then, the other performances are measured by an apparatus in right range of fragmentation. The results of the test indicated that every performance of this device is better than the corresponding value of JB/T10293-2001 when the dropping frequency isn't above 16.47 per second.The study lay the foundation for farther optimized design, meanwhile it can be as an important reference for designing new precision metering device.
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