基于秧针静轨迹的分插机构非圆齿轮求解

Computation Method of Non-circular Gear Based on Seedling Needle Tip Point's Static Trajectory in Transplanting Mechanism

针对目前插秧机的旋转式分插机构非圆齿轮的节曲线均采用函数表达式设计方法的局限性,提出通过理想的秧针静轨迹直接求解分插机构的行星轮系中非圆齿轮传动比的设计方法。利用数值分析的方法由秧针静轨迹求解行星架与行星轮自转的传动比,根据旋转式分插机构行星轮系结构的对称性特点,把非圆齿轮之间的传动比以π为周期分段,建立分段传动比之间的关系和分段传动比与行星架与行星轮自转传动比的关系。在满足轮系总传动比的条件下,提出非圆齿轮的半圆正齿节曲线假设,解决了求解分段传动比有效方程不够的问题。通过对求解出的非圆齿轮系分插机构的三维建模和动态仿真,验证了提出的基于秧针静轨迹求解分插机构非圆齿轮节曲线的方法正确。

A new design method of planetary gear train＇s non-circular gear ratio of transplanting mechanism is presented by analyzing perfect seedling needle tip point＇s static trajectory, aiming at the limitation of non-circular gear pitch curve＇s design method in rice transplanter＇s rotary mechanism at present. The transmission ratio between planet carder and rotation velocity of planet gear is solved by analyzing seedling needle tip point＇s static trajectory using the method of numerical analysis. The relationships of segmented transmission ratios, and the relationships between segmented transmission ratios and the transmission ratio between planet carrier and rotation velocity of planet gear are established by sectioning the transmission ratios of non-circular gear with a period of Tr on the basis of the symmetry of planetary gear train of rotary transplanting mechanism. Under the condition of total transmission ratios, the half spur gear assumption of non-circular gear is presented, and the problem of shortage of equations which are effective to solve the transmission ratios is solved. The correctness of computation method of non-circular gear based on seedling needle tip point＇s static trajectory in transplanting mechanism is verified by three dimensional mode design and kinematics simulation of calculated non-circular gear trains.