Design and optimization of transverse differential speed conveying device for horizontal rapeseed windrower

<bold>Objective</bold> Segmented harvesting of rapeseed includes two stages：windrowing and pickup threshing.This method has advantages such as low loss rate，long period of suitable harvesting，and high-quality rapeseed.To address the challenges of stem detachment from the spreading platform，susceptibility to clogging，and significant variations in stem laying angles during the operation of a horizontal rape windrower machine，Based on the planting patterns，biological characteristics of rapeseed and the requirements for windrowing，a transverse differential speed conveying device for horizontal rapeseed windrower was designed by adopting the differential speed chain-tooth conveying method. <bold>Method</bold> The horizontal rapeseed windrower adopts a tracked combine harvester’s traveling system as its power chassis.The transverse differential conveying device is attached to the conveyor trough of the combine harvester，enabling the machine to complete cutting，conveying，and laying operations in a single pass.This design employs a differential gear conveying mechanism.Key components，including the differential speed conveying chain，the gear，and the conforming laying platform，have been meticulously structured to ensure efficient stem separation from the platform and to maintain a consistent laying pattern.A thorough kinematic analysis has been performed on the traverse processes of cutting，horizontal conveyance，and lateral throwing of rape stems.This analysis has led to the development of a mathematical model for the laying process，and the key factors influencing the laying angle of rapeseed stalks were identified. <bold>Result</bold> A simulation model of the rapeseed stem windrowing process was built based on EDEM.Taking the tine speed ratio，platform inclination angle，and forward speed as factors and the stem laying angle as the evaluation index，a Box-Behnken simulation experiment was conducted.An optimization objective function was established with the goal of minimizing the stem laying angle.Using Design-Expert software，the optimal parameter combination was determined as follows：tine speed ratio of 1.12，platform inclination angle of 22.38°，and forward speed of 1.09 m/s，resulting in an optimal laying angle of 9.54°. <bold>Conclusion</bold> The results of field validation tests show that the average laying angle of rapeseed stems is 10.82°，with a relative error of 11.82% compared with the theoretical value.The average laying width and average laying thickness are 810 mm and 649 mm，respectively.The variation coefficients for laying width and laying thickness are 8.2% and 9.7%，respectively.The windrowing operation process is smooth without blockage，which can meet the actual harvesting requirements.This research provides a reference for the structural design and optimization of the conveying device of horizontal rapeseed windrowers.