Abstract： An orchard spiral solid fertilizer deep fertilizing machine was designed by Solidworks 2016, and the static stress analysis and the modal analysis of spiral drill bit were carried out by Simulation.The optimization was carried out with the wall thickness of drill shaft as index.The results show that the optimal solution for the wall thickness of drill shaft is 4 cm, and the maximum stress of spiral blade is mainly concentrated at the welding position of lower blade of drill shaft with the maximum value of 121.5 MPa. The weight of drill bit is reduced by 8.04 kg after optimization. The modal analysis results illuminate that the working speed of drill bit can avoid the critical speed to avoid resonance. The deep fertilizing machine can not only control the amount of applied fertilizer accurately, but also realize the continuously mechanized operation of ″digging holes, fertilizing and covering soil″ in the fertilization process. The fertilizing machine can also be adopted in the narrow working environment of mountain orchards.
