Abstract:  In order to solve the problem of the poor cutting effect of the cutters on the degradable cutters in the seedling device of the existing automatic transplanting machine, the cutters in the seedling device were optimized. Using SolidWorks software, the threedimensional models of 24 tooth single and double edge disc cutters, 36 tooth single and double edge disc cutters, and 48 tooth single and double edge disc cutters were established. The finite element static strength analysis of six kinds of disc cutters was carried out using ANSYS software. The simulation results showed that the maximum stress and the maximum strain generated by the 24tooth doubleedged disc cutter during the process of cutting the degradable disc were the minimum values, which were 1.658 4×105 Pa and 8.350 2×10-7 m/m, respectively. According to the stress and strain data obtained from the static analysis, the regression model of the effect of the number of teeth and the shape of the cutting edge on the maximum stress and strain and the test factor response surface were obtained using the DesignExpert, and the regression model equation between the maximum stress and strain and the number of teeth and the shape of the cutting edge was obtained. It was determined that the best combination form of disc cutter was 24 teeth double edge disc cutter. The Modal analysis was carried out to get the 10order vibration shape of the disc cutter. Through analyzing the relationship between natural frequency and speed, it was verified that the rated working speed of the disc cutter was 334 Hz when it normally cut the degradable disc. The critical speed of disc cutter resonance was 202.7 Hz. The critical speed of disc cutter resonance was higher than the actual working speed, and the possibility of resonance was very slight. The cutting test of the disc cutter showed that the qualified rates of the 24tooth doubleedged disc cutter were 88.9%, 86.1%, and 80.6%, respectively, under the rotating speed of 350 r/min, 400 r/min, 450 r/min, which could maintain good cutting stability.

Key words: degradable plug, disc cutter, static strength analysis, modal analysis

摘要： 针对现有的穴盘苗全自动移栽机分苗装置中刀具对可降解穴盘切割效果较差的问题,对分苗装置中的刀具进行优化。运用Soildworks软件分别建立24齿单、双刃圆盘切刀,36齿单、双刃圆盘切刀,48齿单、双刃圆盘切刀的三维模型,运用ANSYS软件对六种圆盘切刀进行有限元静强度分析。仿真结果表明:24齿双刃圆盘切刀切割可降解盘过程中受到的最大应力、产生的最大应变都是最小值,分别为1.658 4×10~5 Pa和8.350 2×10~(-7) m/m。运用Design-Expert软件得到齿数与刃口形状两大因素对最大应力、应变的影响效果的回归方程模型和试验因素响应曲面,确定圆盘切刀的最佳组合形式为24齿双刃圆盘切刀。再对其进行Modal模态分析,得到圆盘切刀的10阶振型,通过固有频率与转速之间的关系,验证圆盘切刀正常切割可降解盘作业时的额定工作转速为33.4 Hz,圆盘切刀发生共振的临界转速为202.7 Hz,圆盘切刀发生共振的临界转速高于实际工作时的转速,发生共振可能性极小,为切割可降解盘的圆盘刀具的优化和设计提供理论依据。通过圆盘切刀的切割试验结果可知24齿双刃圆盘切刀在350 r/min、400 r/min、450 r/min转速条件下的切割合格率分别为88.9%、86.1%和80.6%,可保持良好的切割稳定性。

关键词: 可降解穴盘, 圆盘切刀, 静强度分析, 模态分析