Optimization Design And Experiment On Key Parts Of Combined Tillage Machine Of Rotary And Subsoiling

The subsoiling can damage the structure of plow pan layer.It's can improve the capacity of soil moisture conservation,promote nutrient transfer between the tillage layer and the subsoil layer,and boost roots growth,which will effectively increase crop yield.The rotary tillage can re-break the shallow soil after subsoiling,which can finely crushing soil and leveling terrain to provide a good seed bed for sowing.The subsoiler can effectively cause the plow pan layer to fail needed deep into the soil depths,and therefore it has great tillage resistance.At the same time,if large or hard clods are encountered during the operation of soil crushing roller,it will reduce its soil crushing quality.In addition,the rotary tillage should be carried out as soon as possible after subsoiling to avoid loss of soil moisture and nutrients.Traditional subsoiling and rotary tillage are worked alone,which not only reduces the efficiency of operation,but also affects the working quality because of soil compaction caused by agricultural tractors enter farmland again.In order to realize the combined work pattern of subsoiling and rotary tillage,a combined tillage machine of subsoiling and rotary was designed,and the key parts such as subsoiler and soil crushing roller were optimized.On the one hand,the convex blade was designed on the top of subsoiler-tip to reduce the subsoiling resistance and power consumption in this paper,and the curve expression of convex-blade edge was calculated based on the sliding cutting condition.And the convex-blade subsoiler with convex blade was simulated and analyzed by virtual soil simulation model established by discrete element software EDEM.Meanwhile,the contact force between particles and subsoiler was extracted by EDEM_Addin plug-in used to study the stress and deformation of convex blade subsoiler to verify its structural strength.Furthermore,the self-excited vibration subsoiling device with connetration angle was designed based on drag reduction principle of self-excited vibration.The spring is the core part of the whole device.It parameters was selected and verified through kinematics and mechanics analysis of this device.On the other hand,the cage soil crushing roll with secondary crushing function was designed to improve the problem of poor quality of crushed soil,and its structural parameters were designed.Moreover,the static analysis is used to study the rationality of the frame as an important device connecting various components.The accuracy of virtual soil simulation model,the feasibility of designing convex-blade subsoiler and cage crushing roll,and the operation performance of whole machine are studied by field experiments.And through the experiment in the soil bin,the drag reduction effect of self-excited vibration subsoiling device,and the combined drag reduction effect and working quality of convex-blade subsoiler and self-excited vibration subsoiling device were studied.The major experiment results are as follows:1.The experiments proved that the convex-blade subsoiler has dragged reduction effect compared with stander subsoiler,and the average drag reduction is 10.240 %.The measured values of field results are close to simulation results,and the numerical error is within 3 %~10 %.It's testified to that the soil model basically match the soil mechanical properties and can approximating substitute the real soil environment.2.The self-excited vibration subsoiling device has obvious effect on drag reduction,and the average drag reduction is 9.223 %.The drag reduction is obvious of combine device of convex-blade subsoiler and self-excited vibration subsoiling device,and the average drag reduction is 17.425 %.And its soil fluffy degree and disturbance coefficient is 26.162 % and 77.213 % respectively.Those data verify that the combine device can not only reduce the tillage resistance,but also has excellent working quality.3.The caged soil crushing roller did not appear soil adhesion and congestion during the field experiment,and the soil breaking rate is 84.150 %.But,the soil breaking rate of ordinary soil crushing roll is 71.482 %,which indicates that the caged soil crushing roller can effectively ameliorate the soil breaking effect.4.The operation can effectively meliorate the soil layer structure and reduce the soil bulk density.And the stability coefficient of subsoiling depth,stability coefficient of depth of soil preparation,soil surface flatness and vegetation coverage is 94.918 %,92.484 %,1.171 cm and 93.362 % respectively.All parameters are higher than the requirement of the work quality stander,indicating that the machine has obvious quality of soil preparation.