Design Of Rear Power Take-Off And Synchronous Rape Seeding Device For Rice Combine Harvester

China is a major oilseed rape producing country,but the self-sufficiency rate of oilseed crops in China has been maintained at a low level for many years.As a mainstay oil crop,rape is mainly distributed in the middle and lower reaches of the Yangtze River in China,and is mainly produced in the rice and oil rotation cropping mode.However,the tight stubble of rice oil water-dry rotation,short sowing window of rape,large amount of rice straw,sticky soil and small scattered fields have led to poor conditions of conventional ground machine sowing operation of rape,slow promotion and popularization,and the development level is significantly lower than the previous crop of rice machine harvesting link.To address this problem,the group proposes to explore a new operation method based on the existing crawler rice combine harvester platform,based on a medium to large horsepower rice combine harvester to harvest rice and simultaneous oilseeding of rapeseed(referred to as rice harvesting and oilseeding later).This paper follows the basic technical route of "rice harvesting and oil seeding process route design → power consumption calculation and verification of the whole machine → stability analysis of the whole machine → structural design and analysis of key components → parts processing and procurement → integration of the whole machine → electronic control modification of the whole machine → experimental research and improvement suggestions",and focuses on exploring through the modification and retrofitting of the rice combine harvester based on the rear PTO power output and three-point suspension system,the combined technical solution of no-till sowing,fertilizing and furrowing for rape.The main research contents are as follows:(1)Based on the systematic analysis of the current situation of the development of domestic and foreign oilseed rape mechanized sowing and harvesting machine and furrow opener technology,combined with the existing crawler-type rice combine harvester harvesting operation and oilseed rape sowing process requirements,a crawler-type harvester power platform based on thickening the central spindle of threshing drum and replacing the shaft head,with 2-stage belt drive,to achieve the rear PTO power output function of the harvester The design of the rice harvester and oil seeder is completed by adding a rear three-point suspension system and integrating a disc-type furrow opener and an oilseed rape seeding and fertilizing device.(2)Power consumption calculation and stability analysis of the whole machine.After theoretical calculations,the maximum power consumption of the machine is71.95 k W under the conditions of low and medium operating speed of 0.25 ～ 0.9 m/s.The standard power of the harvester’s engine is 81 k W,which can meet the requirements of the whole machine.The results of stability analysis of the machine in different states show that the pressure of the machine on the soil on the horizontal ground is 22.95 k Pa,the longitudinal tilting moment on the horizontal ground is20841.37 N×m,the maximum safe climbing angle to maintain the longitudinal stability is 24.12°,and the maximum safe slope gradient to maintain the lateral stability is 33.02°.(3)Detailed design of key components of the rice harvesting and oil sowing machine.Specifically,it includes:(1)The threshing drum is modified and dynamic balance test is conducted.The size of the central spindle of the threshing drum of the harvester was determined through theoretical calculation.2375 mm long,460 mm radius,1980 mm long,60 mm outer diameter and 42 mm inner diameter of the central spindle of the threshing drum.The maximum shear stress of the threshing drum center spindle is 30.47 MPa,which is less than the allowable torsional shear stress.After the threshing drum was assembled and tested for dynamic balance,the final unbalance was reduced to 32.56 g,which is in accordance with the relevant standards.(2)The rear drive system of the integrated machine was designed.The power required for furrowing is transmitted from the central spindle of the threshing drum to the rear PTO through the belt drive.(3)A rape sowing and application furrowing assembly was designed on the basis of the 1KS-35 double-disc furrowing machine,and two control modes of manual and automatic with-speed adjustment for sowing and application were designed using the STM32 microcontroller development board.(4)A three-point suspension lifting system was installed on the rear chassis of the all-in-one machine,and the corresponding oil circuit and circuit design were completed to ensure the lifting operation requirements of the rear sowing and application assembly.(4)The whole machine of rice harvesting and oil sowing all-in-one machine was modified with electric control design.After the mechanical part of the processing is completed,cooperate with the enterprise to carry out the electric control modification of the integrated machine.On the basis of not affecting the original manual control operation mode,the electric control modification of the vehicle start-stop,travel steering,front and rear suspension,main operation clutch and other systems is completed by adding angle sensors,window motors,push rod motors,solenoid proportional valves and other components.Field test verification of the prototype machine.The soil moisture content was30.06% at the time of test,and under the operating conditions of target trenching depth of 250 mm and travel speed of 0.25 m/s,the actual operating trench depth was255.375 mm on average,the average trench width was 313.125 mm,the stability coefficient of trench depth was 98.74%,the stability coefficient of trench width was97.84%,the trenching work was smooth,and the soil was mainly dispersed within 2.8m from the center of the trench.The seeds and fertilizers can be discharged normally within 2.8 m from the center of the ditch,which is the expected target of the first prototype.