组合式非圆齿轮行星轮系取苗机构动力学分析与试验

Dynamics Analysis and Tests on Seedling Pick-up Mechanism of Planetary Gear Train of Combined Gear Transmission with Non-circular Gears

针对组合式不完全偏心圆-非圆齿轮行星轮系旋转式取苗机构,应用动态静力分析法和动力学方程组序列求解法,建立机构动力学模型,开发出机构动力学分析软件求解模型,计算得到机构链条受力、各齿轮旋转中心和啮合点受力、支座反力的变化规律;建立了机构虚拟样机,加工出机构物理样机,开展机构动力学仿真分析和台架试验,得到两种情况下机构转速为60 r/min时支座反力与行星架转角之间的关系,取苗机构理论分析、仿真分析和台架试验所得到的支座反力变化规律基本一致,验证了取苗机构动力学模型的可靠性和动力学分析的正确性;与原取苗机构比较,本文取苗机构样机y方向支座反力的最大幅值和方差分别从155 N和1 171 N2减小为77 N和553 N2,降低了50. 3%和52. 7%,表明提出的取苗机构具有比原机构更优的动力学性能。

Dynamics characteristics and relative tests on a type of rotary seedling pick-up mechanism of planetary gear train with combined gear transmission of incomplete eccentric circle gear and non-circular gears were studied. Based on the force analysis of each moving component in the seedling pick-up mechanism with the dynamic static analysis method and dynamics equations sequence-solution method, the dynamics mathematical model of the mechanism was built, and the dynamics analysis software was developed to solve the model to obtain the force variation law of different positions, including the chain, rotary centers and mesh points of gears and bearing of the mechanism. The virtual prototype of the mechanism was set up and its physical prototype was manufactured to conduct dynamics simulation analysis and bench tests on the mechanism, respectively. The relationship between the bearing reaction force and the rotation angle of the planetary carrier was obtained when the mechanism was rotated at 60 r/min. The variation law of bearing reaction force under theoretical analysis, dynamics simulation and bench test of the seedling pick-up mechanism were basically consistent, which verified reliability of the dynamics model and correctness of dynamics analysis of the seedling pick-up mechanism. By contrast to the original seedling pick-up mechanism, it can be obtained that the maximum amplitude and variance of bearing reaction force in the y direction of the seedling pick-up mechanism were reduced from 155 N and 1 171 N^2 to 77 N and 553 N^2, which were decreased by 50.3% and 52.7%, respectively, indicating that the mechanism had better dynamics performance than the original mechanism.