基于黄牛舌尖丝状乳突结构的仿生脱粒齿形设计与试验

Bionic Design and Experiment of Threshing Tooth Based on Structure of Cattle Apex Tongue Filiform Papillae

为解决小麦机械脱粒过程中脱净率低的问题,以牛舌舌尖表面丝状乳突结构为仿生原型,开展了小麦仿生脱粒齿形设计与试验。对牛舌舌尖表面进行形貌特征观测,发现舌尖表面丝状乳突分布密度大,结构特征明显,丝状乳突的轮廓呈圆锥状,下粗上细,整体相对粗壮,尖部呈半球形,与牛舌表面呈35°~40°夹角,向口腔方向倾斜。构建“乳突-物料”接触工作界面,包括完全分离、初始接触、乳突插入物料及完全接触4个过程。基于丝状乳突结构特征参数,构建仿生齿形模型,进行单仿生齿形脱粒仿真试验,得到单仿生齿形脱粒最优参数组合:放大比例为2.5、行进速度为15mm/s、倾角为38°、接触位置为齿形全高度的0.2倍处、材料为Q345碳钢。设计了仿生脱粒齿形试验部件及台架,进行仿生脱粒齿形正交试验,并对脱粒过程进行摄像分析。结果表明,仿生脱粒齿形试验部件的脱粒性能良好,脱净率介于97.5%~99.5%之间;最优结构参数组合为:放大比例2.565、倾角39.8°、脱粒间隙9.11mm。

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,papillae-material 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,15 mm/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 9.11 mm.