Design And Experimental Research On Inner Suction-type Precision Hill-drop Seed Metering Device For Rice

In this paper,Aiming at the problems of precision hill-drop seed metering device for rice such as the low qualified rate of seed number,poor cavitation,uneven point spacing and poor adaptability of varieties,which are commonly found.According to the agronomic requirements of precision hill-drop of hybrid rice,combined with the mechanical stirring of the socket ring,precision sucking of group holes and the guide seed of fixed pitch cavitation of impeller,a new type of inner suction-type precision hill-drop seed metering device for rice was innovatively putting forward.The test of material characteristic parameters of rice seed was carried out.The material characteristic parameters of rice seed were tested.The main structural design of the seed metering device and the analysis of the seed-metering mechanism were carried out.EDEM software was utilized to simulate the seed guiding process of the seed metering device.The seed absorbing performance test,inoculation performance test and bench seeding performance test of the seed metering device were carried out successively.Through the analysis of the test results,the optimal structure and the combination of working parameters of the seed metering device were obtained.In order to provide theoretical reference and technical support for the application of precision hill-drop equipment of rice.The main contents are as follows:1)Agricultural material characteristics of slender Chuangliangyou 4418,Zhongnong 2008 of medium length and short Yangguang 800 three typical sizes hybrid rice varieties suitable for planting in the middle and lower reaches of the Yangtze river were tested.Key parameters such as water content,triaxial size,1000-grain weight,density,repose angle and sliding friction angle of rice seed were obtained respectively.It provides reference for the design of key parts,the relevant theoretical analysis and the simulation research.2)Based on the material characteristics of rice and the agronomic requirements of precision hill-drop of hybrid rice.An inner suction-type precision hill-drop seed metering device was developed.An innovative design of impeller seed transmitting parts was presented.The process of filling seed,sucking,receiving seed and throwing seed by seed extractor was analyzed theoretically.3)according to the material characteristics of rice seed,granule models of three varieties of rice were established respectively by EDEM software.The main discrete element parameters are calibrated by simulation test.The simulation study on seed guiding process of seed metering device was carried out,and the suitable seed throwing angle of seed metering device was defined.4)Through the establishment of a test bench for seed suction performance,and with the help of a test bench for the performance of JPS-12 seed metering device,the performance tests of sucking,receiving seed,and throwing seed were carried out.The effects of sucking hole diameter,rice seed sphericity and sucking negative pressure on the seed suction performance of seed metering device were investigated,and the appropriate suction negative pressure and sucking hole diameter of three varieties of rice were obtained respectively.With this as the prerequisite,the single factor test was carried out on the inner impeller radius,offset angle of vane and seed throwing angle with the object of Chuangliangyou 4418.Based on the above test results,the optimal combination of working parameters corresponding to different rice varieties was obtained.Finally,the bench test was carried out on the seed metering device on the optimal combination of working parameters,and throwing seed performance of impeller seed guiding and seed guiding pipe was compared and analyzed.