不完全非圆齿轮行星轮系水稻钵苗移栽机构的动态特性研究
Research on the dynamic characteristics of incomplete non-circular planetary gear train's transplanting mechanism for rice pot seedlings
陆汤飞 1俞亚新 1孙良1
作者信息
- 1. 浙江理工大学机械工程学院,杭州 310018
- 折叠
摘要
针对水稻钵苗移栽机构长期工作后因夹苗片松弛导致取苗准确率下降的问题,考虑齿轮的时变啮合刚度,对移栽机构展开动态特性研究.首先,将不完全非圆齿轮等效为圆柱齿轮,采用改进势能法对两级不完全非圆齿轮副的时变啮合刚度进行求解;建立移栽机构的弹性动力学模型,完成移栽机构模态分析.然后,采用RecurDyn建立移栽机构的动力学仿真模型,完成移栽机构模态仿真,获得了机构的前8阶固有频率与振型;对夹苗片进行动力学仿真分析,获得了夹苗片的应力变化.最后,测试并编制夹苗片的工作载荷谱,进行夹苗片疲劳寿命计算.结果表明:移栽机构前8阶固有频率的理论计算结果与仿真计算结果基本一致,第1阶固有频率最小值为112.3 Hz,振型为夹苗片的弯曲变形;夹苗片的弯曲部分应力最大,为355.6 MPa;夹苗片的疲劳寿命为19.4 h,远低于实际使用要求;更换夹苗片材料,试验结果表明夹苗片疲劳寿命大于200.0 h,满足移栽机构长期工作的需求.该研究可为不完全非圆齿轮副的时变啮合刚度计算提供理论依据,促进移栽机构动态特性研究的进程,同时也为移栽机构的优化设计提供技术支持与参考.
Abstract
Aiming at the problem of accuracy decreasing in seedling picking due to the relaxation of the seedling clamping piece after long-term operation of the rice pot seedling transplanting mechanism,the dynamic characterization of the transplanting mechanism was carried out by taking into account the time-varying meshing stiffness of the gears.Firstly,the incomplete non-circular gear was equivalent to a cylindrical gear,and the time-varying meshing stiffness of the two-stage incomplete non-circular gear pair was solved by the improved potential energy method.An elastic dynamics model of the transplanting mechanism was established,and the modal analysis of the transplanting mechanism was completed.Subsequently,a dynamics simulation model of the transplanting mechanism was established by using RecurDyn,and a modal simulation of the mechanism was completed,resulting in the first eight orders of intrinsic frequency and vibration pattern.A dynamics simulation analysis of the seedling clamping piece was conducted,and the stress change of the seedling clamping piece was obtained.Finally,the working load spectrum of the seedling clamp was tested and compiled,and a fatigue life calculation of the seedling clamp was carried out.The results indicated that the theoretical calculation results of the first eight orders of the transplanting mechanism and the simulation results were largely consistent.The minimum value of the first order of the intrinsic frequency was 112.3 Hz,and the vibration mode was the bending deformation of the seedling clamping piece.The bending part of the seedling clamping piece had the greatest stress,reaching 355.6 MPa;the fatigue life of the seedling clamping piece was 19.4 h,considerably lower than the actual operational requirements;as for the replacement of the material of the seedling clamping piece,the experimental indicated that the fatigue life of the seedling clamping piece exceeded 200.0 h,meeting the needs of long-term operation of transplanting mechanisms.This study provides a theoretical basis for the calculation of time-varying meshing stiffness of incomplete non-circular gear pairs,promotes the process of research on the dynamic characteristics of transplanting mechanisms,and provides technical support and reference for the optimal design of transplanting mechanisms.
关键词
移栽机构/不完全非圆齿轮/时变啮合刚度/模态分析/疲劳分析Key words
transplanting mechanism/incomplete non-circular gear/time-varying meshing stiffness/modal analysis/fatigue analysis引用本文复制引用
出版年
2024
NETL
NSTL
万方数据