Research On The Expression Method Of Rape Pod Shatter Resistance And Optimization Design Of Rape Header's Reel

China is a big country in rape industry,which ranks first in the world in terms of planting area and output of rape.In order to exploring a good variety of rapeseed which is not easy to burst,this paper studied and analyzed the method on the characterizing the pod shatter resistance.Based on random collision method,a collision detection device of pod shatter resistance was designed and made.The effects of water content and size of rape pods on the pod shatter resistance were analyzed and compared with the impending fracturing method.In order to solve the problem of high loss rate of rape combine harvester header in the working stage,this paper analyzed and optimized the trajectory and parameters of the reel.The structure of the reel was optimized and threedimensional modeling and simulation analysis of new type reel were made Field experiments were carried out to compare and analyze the header loss rate of the tine vertical and oblique insertion.Single-factor and multi-factor experiments were carried out with three parameters: rotational speed,machine speed and vertical position of the reel.The most suitable harvesting mode and combination of working parameters were obtained according to the experimental data.The main contents include the following aspects:(1)Research on the expression method of pod shatter resistance.Based on random collision method,a collision detection device of pod shatter resistance was designed and made.The effects of moisture content and size of rape pods on the pod shatter resistance with different varieties were analyzed and compared with the impending fracturing method.The results showed that the rape pod shatter resistance decreased with the decrease of moisture content under the condition of low moisture content.There was a linear correlation between the pod shatter resistance and moisture content.The index and strength of rapeseed pod shatter dehiscence increased with the increasing size.(2)Theoretical analysis and parameter optimization of rape combine harvester reel.Combining with the multi-branching characteristics of rape,the trajectory of the reel was analyzed.The structure and working parameters of the reel,such as diameter,position and rotational speed,were optimized.The diameter of the reel should be 900 mm according to the size of general machine.Considering the characteristic of rapeseed pod dehiscence,the reel should move horizontally towards the inside of the header,the vertical distance between the center of the reel and the cutter should be greater than the sum of the height of the centroid of rape and the radius of reel,the range of rotation speed of reel should be between 11 r/min and 23 r/min.Based on the ‘arborescence' characteristics of multi-branched rape,the insertion process of reel was divided into two stages: inefficient stage and efficient stage.The collision loss can be reduced by the way of oblique insertion of tine during the insertion stage and the phenomenon of wrapping grass can be avoided by the way that inclination angle closed to 0° in the process of separating grains.A new reel and its parameters were designed.A collision mechanics model between the pulley and rape was established.(3)Three-dimensional modeling and simulation analysis of new type reel.The 3-D model of the new reel was built by solidworks.Kinematics simulation analysis was carried out by ADAMS,and the theoretical trajectories and displacement curves of tinebar and tine were obtained.Kinematics analysis showed that the new eccentric pulling wheel can work normally.The trajectories of tinebar and tine could push the rape into the header.In the entry stage,the trajectory of the tine vertex was obliquely below the trajectory of the tinebar and it indicated that the tine was obliquely inserted.In the departure stage,the tine vertex trajectory was below the trajectory of the tinebar.It indicated that the inclination angle of the tine was gradually reduced and the phenomenon of wrapping grass could be prevented.(4)Field test of rape combine harvester.Taking the reel loss rate as an evaluation index,the single factor experiments were carried out on the three influencing factors of rotational speed,machine speed and vertical position of the reel.The header loss rates with vertical insertion and oblique insertion of tine were compared.The experiment showed that the three parameters have an effect on the header loss rate.The most significant effect was the rotational speed of reel.The loss rate of the header with oblique insertion of tine was lower than that with vertical insertion.On the basis of single factor experiment,multi-factor orthogonal experiments were carried out by the way of oblique insertion of tine.The influence order was rotation speed,machine speed and horizontal position.Based on the regression model,the optimal parameter combination was that the rotational speed was 18r/min,the machine speed was 500 mm,and the vertical position was 1200 mm.The header loss rate was 0.96% with the optimal parameter combination by computer.The real header loss rate was 1.04% in the field test.It proved that the model was reliable.