| Threshing unit were researed and developed in order to improve axial flow combine harvester's performance and satisfy farmers requirements. The work was funded by National Ministry of Science and Technology. The best plan was confirmed by researching the theory of structure and motion parameters about threshing unit, orthogonal test, and analyzing these parameters' effects on combine harvester's performance.Main conclusions and suggestions are as following:(1) The best plan of the threshing unit is: the type of infeed impeller for threshing rotor is type b, the type of feeding part for concave is type a, the velocity of threshing rotor is 700 r/min. The most important factor to the threshing unit is the type of infeed impeller for threshing rotor. The sawtooth-impeller is a an important technical innovation in threshing unit at home and abroad. And the cost for its manufacture is lower than other, the assemblage faciler too. The most important point is that the threshing performance is very excellent.(2)The structure of infeed impeller is the most important factor to entrainment loss rate of grain. Entrainment loss rate of grain is lower when using staff -tooth impeller or sawtooth-impeller. But the staff -tooth impeller lack for the capability to make the grain flow, so it's not fit for axial flow combine harvester.(3)The most important factor to the seed broken rate is the velocity of threshing rotor. The seed broken rate is lower when the of threshing rotor is 700 r/min. And it will rises while the velocity of threshing rotor being increased., the optimal velocity is 700 r/min which is the lowest velocity in this orthogonal test. So we can get optimal plan by slowering the velocity of threshing rotor.(4) The Oriented part for Concave is worse when making holes on it.(5) The type of infeed impeller for threshing rotor is the most important factor to grain distribution. And it's better to choose sawtooth-impeller to improve grain distribution. |
PDF Full Text Request