Dropping Simulation Analysis And Optimization Of Knapsack Safflower Harvesting Machine

In this paper, knapsack safflower harvesting machine damaged,vulnerable parts picking system,or system internal structure assembly relationships disordered due to improper operation, negligence,operator fatigue and other accident conditions make it drop accidentally, and causing it to suffer a strong drop impact,which can affect their performance. Therefore, based on the basic theory of explicit dynamic analysis, the entire dropping process of knapsack safflower harvesting machine are analyzed,to improve the knapsack safflower harvester reliability in use,it has good resistance to drop,impact resistance,prolong its life and solve knapsack red harvester weak parts and structure optimization.1. The drop condition analysis of the knapsack type safflower harvest machine. The reasonable range of the roller clearance is 0.4mm-0.6mm, which is the important parameter to judge whether or not to reach the damage or failure after hand-held system dropping, through experimental study and etc. Determine the characteristic parameters of safflower plants,plant morphological characters,safflower balls spatial distribution and branch angle through test and study, field research to ensure knapsack safflower machine of hand-held system of five typical drop posture, suspension system three kind of typical drop posture and the drop damageable parts of picking handle in process of using.The drop impact equation is established by the basic theory of drop impact, which provides a theoretical basis for the follow-up drop simulation.2. The establishment of finite element model of knapsack safflower harvest machine and drop simulation analysis. By using the finite element analysis software ABAQUS to establish finite element of safflower harvest machine model, combined with the explicit dynamic method to operate drop simulation under different poses on the hand-held system, suspension system. By drop analysis found that at the lugs and the front end of the handle housing hand-held system cover the most prone to stress concentration and fracture in the front gear hand-held system in drop usually bear the whole system and the ground impact force exceeds the yield strength of lead gear failure, resulting in the assembly of each component loosening the reasonable range, the dislocation, the roller clearance is far more than 0.4mm-0.6mm, the hand-held system invalid; The weak components for the transmission shaft and the fan baffle when suspension system drops,The main function of the stress concentration caused by bolt hole torn in bolt holes when baffle suffer drop impact.Fan transmission stress concentration resulting in the rupture of shaft the main fan in the side vertical drop impact, seriously affect the stability and reliability of the system with work. Through the simulation, obtain the weak position of the hand-held system and the suspension system in the process of dropping, which provides a reference for the optimization design of the whole machine against dropping and improve the reliability.3. In order to improve the reliability of knapsack safflower harvest machine, which has good anti-drop capability, prolong the service life, this thesis aim at find weak parts in the drop simulation to optimize structure. For the hand-held system structure optimization:to avoid stress concentration phenomenon appears in the handle shell and the front cover of the lug to propose remove the lug of the shell of the handle, the front end cover lug concave and the handle is connected with a housing of an optimization scheme, using yield strength and other performance parameters of PP -36370 plastic materials instead of PP-3050; to reduce the gear suffer direct sharp drop impact, to install the gear position moves to the rear end of the handle which is connected through a bearing and a roller. The simulation results show that the optimized hand-held system demand the requirements of the drop impact strength, the structure is more solid, in the same drop posture the roller clearance were between the 0.4mm-0.6mm, therefore the optimized structure has high reliability and good anti-drop impact capability. For suspension system structure optimization:to reducing positioning plate, mounting plate bolt holes at the stress concentrated destruction,enlarge the bolt hole with rigid material insert, enlarge the contact area; to prevent the wind turbine power shaft from damaging by strong impact load, and combined with mechanical balance calculated in the stress concentrated part of the spindle diameter increases to 28mm.