Abstract:Threshing is an important working operation in wheat harvesting process. However, low threshed rate is an important problem restricting threshing operation, so it is urgent to innovate threshing mechanism and improve threshing parts. Cattles were typical ruminants and their tongues provided a natural biological model for bionic threshing. The filiform papillae was observed on the surface of the tongue tip of cattle by scanning electronic microscope. The distribution density of filiform papillae was large, and its structural characteristics were obvious. Its outline was conical, and its tip was hemispherical. The filiform papillae was inclined and the inclination angle was 35°~40°. The “papillae-material” contact working interface was constructed, including four working steps of complete separation, initial contact, papillaematerial insertion and complete contact. Based on structural characteristic parameters of filiform papillae, the bionic tooth model was constructed and the simulation test of bionic tooth threshing was carried out. The optimal combination of parameters for bionic tooth threshing was obtained. The optimal combination was 2.5 times magnify ratio, 15mm/s movement speed, 38° inclination angle, contact position for 0.2 times the height of tooth form the whole place, Q345 material. The bionic tooth threshing bench test was carried out and the threshing process was analyzed by camera. The regression model and response surfaces were established by orthogonal test. Response surface analysis showed that the threshing performance of bionic tooth was good, and the threshed rate was ranged from 97.5% to 99.5%. The optimal structure parameter combination of bionic tooth was obtained. The magnify times was 2.565, the inclination angle was 39.8°, and the threshing clearance was 9.11mm.
